Firepower威胁防御IGMP和组播基础故障排除

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已更新: 2022 年 5 月 19 日

文档 ID:217891

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简介

本文档介绍组播的基础知识，以及Firepower威胁防御(FTD)如何实施互联网组管理协议(IGMP)。

先决条件

要求

基本IP路由知识。

使用的组件

本文档中的信息都是基于特定实验室环境中的设备编写的。本文档中使用的所有设备最初均采用原始（默认）配置。如果您的网络处于活动状态，请确保您了解所有命令的潜在影响。

本文内容也适用于自适应安全设备(ASA)软件。

本文档中的信息基于以下软件和硬件版本：

思科Firepower 4125威胁防御版本7.1.0。
Firepower管理中心(FMC)版本7.1.0。
ASA 9.19.1 版.

背景信息

定义

单播=从一台主机到另一台主机（一对一）。
广播=从一台主机到所有可能的主机（一对全）。
组播=从一组主机的主机到一组主机（一对多或多对多）。
任播=从主机到组的最近主机（一对多对一）。

基本信息

组播RFC 988由Steve Deering于1986年编写。
IPv4组播使用的范围是224.0.0.0/4（前4位1110） — 224.0.0.0 - 239.255.255.255。
对于IPv4，第2层MAC地址来自第3层组播IP:01005e（24位）+第25^{位，始终为0 +组播IPv4地址的低}23位。
IPv6组播使用范围FF00::/8，它比IPv4组播更灵活，因为它可以嵌入交汇点(RP)IP。
对于IPv6,L2 MAC地址来自L3组播：333 + 32位组播IPv6地址。
组播优势：由于源上的负载减少，效率提高。性能，因为它避免了流量重复或泛洪。
组播的缺点：传输不可靠（基于UDP）、无拥塞避免、传输顺序不当。
公共互联网不支持组播，因为它需要路径中的所有设备才能启用组播。通常，当所有设备都受同一管理权限管理时使用。
典型组播应用：内部视频流、视频会议。

组播与复制单播

在复制单播中，源创建同一单播数据包（副本）的多个副本，并将它们发送到多个目标主机。组播将负担从源主机转移到网络，而在复制单播中，所有工作都在源主机上完成。

配置

IGMP基础知识

IGMP是组播接收器和本地L3设备（通常为路由器）之间的“语言”。
IGMP是第3层协议（与ICMP类似），使用IP协议编号2。
当前有3个IGMP版本。防火墙上的默认IGMP版本是版本2。当前仅支持版本1和2。
IGMPv1和IGMPv2之间的主要区别如下：

IGMPv1没有离开组消息。
IGMPv1没有特定于组的查询（当主机离开组播组时，防火墙会使用它）。
IGMPv1没有查询器选举过程。

ASA/FTD目前不支持IGMPv3，但作为参考，IGMPv2和IGMPv3之间的重要区别在于IGMPv3中包含组和源特定查询，该查询用于源特定组播(SSM)。
IGMPv1/IGMPv2/IGMPv3查询= 224.0.0.1
IGMPv2离开= 224.0.0.2
IGMPv3成员报告= 224.0.0.22
如果主机要加入，可以发送未经请求的IGMP成员身份报告消息：

igmp_membership

从防火墙的角度来看，IGMP查询有两种类型：常规查询和特定组的查询
当防火墙收到IGMP离开组消息时，它必须检查该子网上是否有该组的其它成员。因此，防火墙会发送组特定查询：

igmp_membership_specific

在有多台路由器/防火墙的子网上，选择querier（发送所有IGMP查询的设备）：

firepower# show igmp interface INSIDE
INSIDE is up, line protocol is up
  Internet address is 192.168.1.97/24
  IGMP is enabled on interface
  Current IGMP version is 2
  IGMP query interval is 125 seconds
  IGMP querier timeout is 60 seconds
  IGMP max query response time is 10 seconds
  Last member query response interval is 1 seconds
  Inbound IGMP access group is:
  IGMP limit is 500, currently active joins: 2
  Cumulative IGMP activity: 21 joins, 20 leaves
  IGMP querying router is 192.168.1.97 (this system)  <-- IGMP querier

在FTD上（类似于传统ASA），您可以启用debug igmp以查看与IGMP相关的消息：

firepower# debug igmp
IGMP debugging is on
IGMP: Received v2 Query on DMZ from 192.168.6.1
IGMP: Received v2 Report on INSIDE from 192.168.1.50 for 239.255.255.250   <-- Received an IGMP packet
IGMP: group_db: add new group 239.255.255.250 on INSIDE
IGMP: MRIB updated (*,239.255.255.250) : Success
IGMP: Switching to EXCLUDE mode for 239.255.255.250 on INSIDE
IGMP: Updating EXCLUDE group timer for 239.255.255.250
IGMP: Received v2 Report on INSIDE from 192.168.1.50 for 230.10.10.10
IGMP: group_db: add new group 230.10.10.10 on INSIDE
IGMP: MRIB updated (*,230.10.10.10) : Success
IGMP: Switching to EXCLUDE mode for 230.10.10.10 on INSIDE
IGMP: Updating EXCLUDE group timer for 230.10.10.10
IGMP: Send v2 general Query on INSIDE
IGMP: Received v2 Query on INSIDE from 192.168.1.97
IGMP: Send v2 general Query on OUTSIDE
IGMP: Received v2 Query on OUTSIDE from 192.168.103.91
IGMP: Received v2 Report on INSIDE from 192.168.1.50 for 239.255.255.250
IGMP: Updating EXCLUDE group timer for 239.255.255.250
IGMP: Received v2 Report on INSIDE from 192.168.1.50 for 230.10.10.10
IGMP: Updating EXCLUDE group timer for 230.10.10.10

主机通常使用离开组消息(IGMPv2)离开组播组。

igmp_leave

任务1 — 控制平面组播流量

OSPF_topology

在FTD和ASA之间配置OSPFv2和OSPFv3。检查2台设备如何处理OSPF生成的L2和L3组播流量。

解决方案

OSPFv2配置

ospf_config_ftd

ospf_config_interface

同样，对于OSPFv3

FTD CLI上的配置：

router ospf 1
 network 192.168.103.0 255.255.255.0 area 0
 log-adj-changes
!
ipv6 router ospf 1
 no graceful-restart helper
 log-adjacency-changes
!
interface Ethernet1/4
nameif OUTSIDE
security-level 0
ip address 192.168.103.91 255.255.255.0
ipv6 address fc00:103::91/64
ospf authentication null
ipv6 ospf 1 area 0

配置会在FTD加速安全路径(ASP)允许表中创建以下条目，以便入口组播流量不会被阻止：

firepower# show asp table classify domain permit
...
in id=0x14f922db85f0, priority=13, domain=permit, deny=false         <-- permit the packets
        hits=1, user_data=0x0, cs_id=0x0, reverse, flags=0x0, protocol=89
        src ip/id=0.0.0.0, mask=0.0.0.0, port=0, tag=any
        dst ip/id=224.0.0.5, mask=255.255.255.255, port=0, tag=any, dscp=0x0, nsg_id=none     <-- OSPF for IPv4
        input_ifc=OUTSIDE(vrfid:0), output_ifc=identity(vrfid:0)     <-- ingress interface
in id=0x14f922db9350, priority=13, domain=permit, deny=false         <-- permit the packets
        hits=0, user_data=0x0, cs_id=0x0, reverse, flags=0x0, protocol=89
        src ip/id=0.0.0.0, mask=0.0.0.0, port=0, tag=any
        dst ip/id=224.0.0.6, mask=255.255.255.255, port=0, tag=any, dscp=0x0, nsg_id=none     <-- OSPF for IPv4
        input_ifc=OUTSIDE(vrfid:0), output_ifc=identity(vrfid:0)     <-- ingress interface

对于IPv6:

...
in id=0x14f923fb16f0, priority=13, domain=permit, deny=false      <-- permit the packets
        hits=1, user_data=0x0, cs_id=0x0, reverse, flags=0x0, protocol=89
        src ip/id=::/0, port=0, tag=any
        dst ip/id=ff02::5/128, port=0, tag=any, , nsg_id=none     <-- OSPF for IPv6
        input_ifc=OUTSIDE(vrfid:0), output_ifc=identity(vrfid:0)  <-- ingress interface
in id=0x14f66e9d4780, priority=13, domain=permit, deny=false      <-- permit the packets
        hits=0, user_data=0x0, cs_id=0x0, reverse, flags=0x0, protocol=89
        src ip/id=::/0, port=0, tag=any
        dst ip/id=ff02::6/128, port=0, tag=any, , nsg_id=none     <-- OSPF for IPv6
        input_ifc=OUTSIDE(vrfid:0), output_ifc=identity(vrfid:0)  <-- ingress interface
...

OSPFv2和OSPFv3邻接关系为UP:

firepower# show ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
192.168.103.50 1 FULL/BDR 0:00:35 192.168.103.50 OUTSIDE   <-- OSPF neighbor is up

firepower# show ipv6 ospf neighbor
Neighbor ID Pri State Dead Time Interface ID Interface
192.168.103.50 1 FULL/BDR 0:00:34 3267035482 OUTSIDE       <-- OSPF neighbor is up

以下是终止到该设备的组播OSPF会话：

firepower# show conn all | include OSPF
OSPF OUTSIDE fe80::2be:75ff:fef6:1d8e NP Identity Ifc ff02::5, idle 0:00:09, bytes 5924, flags
OSPF OUTSIDE 192.168.103.50 NP Identity Ifc 224.0.0.5, idle 0:00:03, bytes 8904, flags
OSPF OUTSIDE ff02::5 NP Identity Ifc fe80::f6db:e6ff:fe33:442e, idle 0:00:01, bytes 6304, flags
OSPF OUTSIDE 224.0.0.5 NP Identity Ifc 192.168.103.91, idle 0:00:00, bytes 25220, flags

作为测试，启用IPv4捕获并清除与设备的连接：

firepower# capture CAP interface OUTSIDE trace
firepower# clear conn all
12 connection(s) deleted.
firepower# clear capture CAP
firepower# !

警告：这会导致中断！显示的示例仅用于演示目的！

捕获的OSPF数据包：

firepower# show capture CAP | include proto-89
1: 12:25:33.142189 192.168.103.50 > 224.0.0.5 ip-proto-89, length 60
2: 12:25:33.702691 192.168.103.91 > 224.0.0.5 ip-proto-89, length 60
7: 12:25:36.317000 192.168.206.100 > 224.0.0.5 ip-proto-89, length 56
8: 12:25:36.952587 fe80::2be:75ff:fef6:1d8e > ff02::5 ip-proto-89 40 [flowlabel 0xe] [hlim 1]
12: 12:25:41.282608 fe80::f6db:e6ff:fe33:442e > ff02::5 ip-proto-89 40 [flowlabel 0xe] [hlim 1]

以下是防火墙处理OSPFv2组播数据包的方式：

firepower# show capture CAP packet-number 1 trace
115 packets captured

1: 12:25:33.142189 192.168.103.50 > 224.0.0.5 ip-proto-89, length 60    <-- The first packet of the flow
Phase: 1
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 6344 ns
Config:
Additional Information:
MAC Access list

Phase: 2
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 6344 ns
Config:
Implicit Rule
Additional Information:
MAC Access list

Phase: 3
Type: ROUTE-LOOKUP
Subtype: No ECMP load balancing
Result: ALLOW
Elapsed time: 10736 ns
Config:
Additional Information:
Destination is locally connected. No ECMP load balancing.
Found next-hop 192.168.103.50 using egress ifc OUTSIDE(vrfid:0)

Phase: 4
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 5205 ns
Config:
Implicit Rule
Additional Information:

Phase: 5
Type: NAT
Subtype: per-session
Result: ALLOW
Elapsed time: 5205 ns
Config:
Additional Information:

Phase: 6
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Elapsed time: 5205 ns
Config:
Additional Information:

Phase: 7
Type: CLUSTER-REDIRECT
Subtype: cluster-redirect
Result: ALLOW
Elapsed time: 29280 ns
Config:
Additional Information:

Phase: 8
Type: MULTICAST
Subtype:
Result: ALLOW
Elapsed time: 976 ns
Config:
Additional Information:

Phase: 9                     
Type: OSPF                   <-- The OSPF process
Subtype: ospf
Result: ALLOW
Elapsed time: 488 ns
Config:
Additional Information:

Phase: 10
Type: FLOW-CREATION
Subtype:
Result: ALLOW
Elapsed time: 13176 ns
Config:
Additional Information:
New flow created with id 620, packet dispatched to next module

Result:
input-interface: OUTSIDE(vrfid:0)
input-status: up
input-line-status: up
output-interface: OUTSIDE(vrfid:0)
output-status: up
output-line-status: up
Action: allow
Time Taken: 82959 ns

以下是防火墙处理OSPFv3组播数据包的方式：

firepower# show capture CAP packet-number 8 trace
274 packets captured

8: 12:25:36.952587 fe80::2be:75ff:fef6:1d8e > ff02::5 ip-proto-89 40 [flowlabel 0xe] [hlim 1]  <-- The first packet of the flow
Phase: 1
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 7564 ns
Config:
Additional Information:
MAC Access list

Phase: 2
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 7564 ns
Config:
Implicit Rule
Additional Information:
MAC Access list

Phase: 3
Type: ROUTE-LOOKUP
Subtype: No ECMP load balancing
Result: ALLOW
Elapsed time: 8296 ns
Config:
Additional Information:
Destination is locally connected. No ECMP load balancing.
Found next-hop ff02::5 using egress ifc identity(vrfid:0)

Phase: 4
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 8784 ns
Config:
Implicit Rule
Additional Information:

Phase: 5
Type: NAT
Subtype: per-session
Result: ALLOW
Elapsed time: 8784 ns
Config:
Additional Information:

Phase: 6
Type: CLUSTER-REDIRECT
Subtype: cluster-redirect
Result: ALLOW
Elapsed time: 27816 ns
Config:
Additional Information:

Phase: 7
Type: OSPF                    <-- The OSPF process
Subtype: ospf
Result: ALLOW
Elapsed time: 976 ns
Config:
Additional Information:

Phase: 8
Type: FLOW-CREATION
Subtype:
Result: ALLOW
Elapsed time: 13664 ns
Config:
Additional Information:
New flow created with id 624, packet dispatched to next module

Result:
input-interface: OUTSIDE(vrfid:0)
input-status: up
input-line-status: up
output-interface: NP Identity Ifc
Action: allow
Time Taken: 83448 ns

任务2 — 配置基本组播

拓扑

要求

配置防火墙，以便将来自服务器的组播流量流传输到IP 230.10.10.10上的组播客户端

解决方案

从防火墙角度来看，最低配置是全局启用组播路由。这将在所有防火墙接口上启用后台IGMP和PIM。

在FMC UI上：

enable_ftd_multicast

在防火墙CLI上，这是推送的配置：

firepower# show run multicast-routing
multicast-routing                   <-- Multicast routing is enabled

IGMP验证

firepower# show igmp interface
diagnostic is up, line protocol is up
  Internet address is 0.0.0.0/0
  IGMP is disabled on interface
INSIDE is up, line protocol is up          <-- The interface is UP
  Internet address is 192.168.1.24/24
  IGMP is enabled on interface             <-- IGMP is enabled on the interface
  Current IGMP version is 2                <-- IGMP version
  IGMP query interval is 125 seconds
  IGMP querier timeout is 255 seconds
  IGMP max query response time is 10 seconds
  Last member query response interval is 1 seconds
  Inbound IGMP access group is:
  IGMP limit is 500, currently active joins: 1
  Cumulative IGMP activity: 4 joins, 3 leaves
  IGMP querying router is 192.168.1.24 (this system)
OUTSIDE is up, line protocol is up         <-- The interface is UP
  Internet address is 192.168.103.91/24
  IGMP is enabled on interface             <-- IGMP is enabled on the interface
  Current IGMP version is 2                <-- IGMP version
  IGMP query interval is 125 seconds
  IGMP querier timeout is 255 seconds
  IGMP max query response time is 10 seconds
  Last member query response interval is 1 seconds
  Inbound IGMP access group is:
  IGMP limit is 500, currently active joins: 1
  Cumulative IGMP activity: 1 joins, 0 leaves
  IGMP querying router is 192.168.103.91 (this system)

firepower# show igmp group
IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter
239.255.255.250 INSIDE 00:09:05 00:03:19 192.168.1.50
239.255.255.250 OUTSIDE 00:06:01 00:02:33 192.168.103.60

firepower# show igmp traffic
IGMP Traffic Counters
Elapsed time since counters cleared: 03:40:48 Received Sent

                              Received     Sent
Valid IGMP Packets            21           207
Queries                       0            207
Reports                       15           0       <-- IGMP Reports received and sent
Leaves                        6            0
Mtrace packets                0            0
DVMRP packets                 0            0
PIM packets                   0            0

Errors:
Malformed Packets             0
Martian source                0
Bad Checksums                 0

PIM验证

firepower# show pim interface

Address          Interface          PIM  Nbr   Hello  DR         DR
                                       Count Intvl  Prior

0.0.0.0          diagnostic         off  0     30     1          not elected
192.168.1.24     INSIDE             on   0     30     1          this system
192.168.103.91   OUTSIDE            on   0     30     1          this system

MFIB验证

firepower# show mfib
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
             AR - Activity Required, K - Keepalive
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second
Other counts: Total/RPF failed/Other drops
Interface Flags: A - Accept, F - Forward, NS - Negate Signalling
             IC - Internal Copy, NP - Not platform switched
             SP - Signal Present
Interface Counts: FS Pkt Count/PS Pkt Count

(*,224.0.1.39) Flags: S K
   Forwarding: 0/0/0/0, Other: 0/0/0   <-- The Forwarding counters are: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second
(*,224.0.1.40) Flags: S K
   Forwarding: 0/0/0/0, Other: 8/8/0   <-- The Other counters are: Total/RPF failed/Other drops
(*,232.0.0.0/8) Flags: K
   Forwarding: 0/0/0/0, Other: 0/0/0

通过防火墙的组播流量

在这种情况下，VLC媒体播放器应用用作组播服务器和客户端来测试组播流量：

multicast_through_ftd

VLC组播服务器配置：

vlc_stream

vlc_add_file

在下一个屏幕上，选择Next。

选择格式：

vlc_add_method

指定组播IP和端口：

vlc_add_ip

vlc_enable

在FTD防火墙上启用LINA捕获：

firepower# capture INSIDE interface INSIDE match ip host 192.168.103.60 host 230.10.10.10
firepower# capture OUTSIDE interface OUTSIDE trace match ip host 192.168.103.60 host 230.10.10.10

为设备选择流按钮以启动组播流：

vlc_start_stream

启用“loop”选项，以便连续发送流：

vlc_loop

验证（非操作场景）

此场景演示了一个非操作场景。目标是演示防火墙行为。

防火墙设备获取组播流，但不转发它：

firepower# show capture
capture INSIDE type raw-data interface INSIDE [Capturing - 0 bytes]     <-- No packets sent or received
match ip host 192.168.103.60 host 230.10.10.10
capture OUTSIDE type raw-data trace interface OUTSIDE [Buffer Full - 524030 bytes]  <-- The buffer is full
match ip host 192.168.103.60 host 230.10.10.10

Firewall LINA ASP drops显示：

firepower# clear asp drop
firepower# show asp drop

Frame drop:
  Punt rate limit exceeded (punt-rate-limit)                         232  <-- The multicast packets were dropped
  Flow is denied by configured rule (acl-drop)                         2
  FP L2 rule drop (l2_acl)                                             2

Last clearing: 18:38:42 UTC Oct 12 2018 by enable_15

Flow drop:

Last clearing: 08:45:41 UTC May 17 2022 by enable_15

要跟踪数据包，需要捕获组播流的第一个数据包。因此，请清除当前流量：

firepower# clear capture OUTSIDE
firepower# clear conn all addr 230.10.10.10
2 connection(s) deleted.

firepower# show capture OUTSIDE

379 packets captured

1: 08:49:04.537875 192.168.103.60.54100 > 230.10.10.10.5005: udp 64
2: 08:49:04.537936 192.168.103.60.54099 > 230.10.10.10.5004: udp 1328
3: 08:49:04.538027 192.168.103.60.54099 > 230.10.10.10.5004: udp 1328
4: 08:49:04.538058 192.168.103.60.54099 > 230.10.10.10.5004: udp 1328
5: 08:49:04.538058 192.168.103.60.54099 > 230.10.10.10.5004: udp 1328
6: 08:49:04.538073 192.168.103.60.54099 > 230.10.10.10.5004: udp 1328
...

“detail”选项显示组播MAC地址：

firepower# show capture OUTSIDE detail

379 packets captured

1: 08:49:04.537875 0050.569d.344a 0100.5e0a.0a0a 0x0800 Length: 106
192.168.103.60.54100 > 230.10.10.10.5005: [udp sum ok] udp 64 (ttl 100, id 19759)
2: 08:49:04.537936 0050.569d.344a 0100.5e0a.0a0a 0x0800 Length: 1370
192.168.103.60.54099 > 230.10.10.10.5004: [udp sum ok] udp 1328 (ttl 100, id 19760)
3: 08:49:04.538027 0050.569d.344a 0100.5e0a.0a0a 0x0800 Length: 1370
192.168.103.60.54099 > 230.10.10.10.5004: [udp sum ok] udp 1328 (ttl 100, id 19761)
...

实际数据包的跟踪显示数据包被允许，但实际发生的情况并非如此：

firepower# show capture OUTSIDE packet-number 1 trace
379 packets captured

1: 08:49:04.537875 192.168.103.60.54100 > 230.10.10.10.5005: udp 64
Phase: 1
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 11712 ns
Config:
Additional Information:
MAC Access list

Phase: 2
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 11712 ns
Config:
Implicit Rule
Additional Information:
MAC Access list

Phase: 3
Type: ROUTE-LOOKUP
Subtype: No ECMP load balancing
Result: ALLOW
Elapsed time: 7808 ns
Config:
Additional Information:
Destination is locally connected. No ECMP load balancing.
Found next-hop 192.168.103.60 using egress ifc OUTSIDE(vrfid:0)

Phase: 4
Type: ACCESS-LIST
Subtype: log
Result: ALLOW
Elapsed time: 5246 ns
Config:
access-group CSM_FW_ACL_ global
access-list CSM_FW_ACL_ advanced permit ip any any rule-id 268434432
access-list CSM_FW_ACL_ remark rule-id 268434432: ACCESS POLICY: mzafeiro_empty - Default
access-list CSM_FW_ACL_ remark rule-id 268434432: L4 RULE: DEFAULT ACTION RULE
Additional Information:
This packet will be sent to snort for additional processing where a verdict will be reached

Phase: 5
Type: CONN-SETTINGS
Subtype:
Result: ALLOW
Elapsed time: 5246 ns
Config:
class-map class-default
match any
policy-map global_policy
class class-default
set connection advanced-options UM_STATIC_TCP_MAP
service-policy global_policy global
Additional Information:

Phase: 6
Type: NAT
Subtype: per-session
Result: ALLOW
Elapsed time: 5246 ns
Config:
Additional Information:

Phase: 7
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Elapsed time: 5246 ns
Config:
Additional Information:

Phase: 8
Type: CLUSTER-REDIRECT
Subtype: cluster-redirect
Result: ALLOW
Elapsed time: 31232 ns
Config:
Additional Information:

Phase: 9
Type: MULTICAST       <-- multicast process
Subtype:
Result: ALLOW
Elapsed time: 976 ns
Config:
Additional Information:

Phase: 10
Type: FLOW-CREATION   <-- the packet belongs to a new flow
Subtype:
Result: ALLOW          
Elapsed time: 20496 ns
Config:
Additional Information:
New flow created with id 3705, packet dispatched to next module

Result:
input-interface: OUTSIDE(vrfid:0)   
input-status: up
input-line-status: up
output-interface: OUTSIDE(vrfid:0)
output-status: up
output-line-status: up
Action: allow            <-- The packet is allowed
Time Taken: 104920 ns

根据mroute和mfib计数器，数据包被丢弃，因为传出接口列表(OIL)为空：

firepower# show mroute

Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group,
C - Connected, L - Local, I - Received Source Specific Host Report,
P - Pruned, R - RP-bit set, F - Register flag, T - SPT-bit set,
J - Join SPT
Timers: Uptime/Expires
Interface state: Interface, State

(192.168.103.60, 230.10.10.10), 00:01:33/00:01:56, flags: SPF
Incoming interface: OUTSIDE          
RPF nbr: 192.168.103.60
Outgoing interface list: Null        <-- The OIL is empty!

(*, 239.255.255.250), 00:01:50/never, RP 0.0.0.0, flags: SCJ
Incoming interface: Null
RPF nbr: 0.0.0.0
Immediate Outgoing interface list:
INSIDE, Forward, 00:01:50/never

MFIB计数器显示RPF故障，在本例中，RPF故障并不是实际发生的情况：

firepower# show mfib 230.10.10.10
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
             AR - Activity Required, K - Keepalive
firepower# show mfib 230.10.10.10
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
AR - Activity Required, K - Keepalive
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second   <-- Multicast forwarding counters
Other counts: Total/RPF failed/Other drops            <-- Multicast drop counters
Interface Flags: A - Accept, F - Forward, NS - Negate Signalling
             IC - Internal Copy, NP - Not platform switched
             SP - Signal Present
Interface Counts: FS Pkt Count/PS Pkt Count

(192.168.103.60,230.10.10.10) Flags: K
   Forwarding: 0/0/0/0, Other: 650/650/0       <-- Allowed and dropped multicast packets

“show mfib count”输出中的类似RPF故障：

firepower# show mfib count
IP Multicast Statistics
8 routes, 4 groups, 0.25 average sources per group
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kilobits per second
Other counts: Total/RPF failed/Other drops(OIF-null, rate-limit etc)
Group: 224.0.1.39
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
Group: 224.0.1.40
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
Group: 230.10.10.10
  Source: 192.168.103.60,
    Forwarding: 0/0/0/0, Other: 1115/1115/0   <-- Allowed and dropped multicast packets
  Tot. shown: Source count: 1, pkt count: 0
Group: 232.0.0.0/8
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
Group: 239.255.255.250
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0

配置VLC组播接收器：

vlc_play_stream

指定组播源IP并选择播放：

在后端中，只要选择播放，主机就会宣布愿意加入特定组播组并发送IGMP报告消息：

multicast_through_ftd_ok

如果启用调试，您可以看到IGMP报告消息：

firepower# debug igmp group 230.10.10.10
IGMP: Received v2 Report on INSIDE from 192.168.1.50 for 230.10.10.10  <-- IGMPv2 Report received
IGMP: group_db: add new group 230.10.10.10 on INSIDE
IGMP: MRIB updated (*,230.10.10.10) : Success
IGMP: Switching to EXCLUDE mode for 230.10.10.10 on INSIDE
IGMP: Updating EXCLUDE group timer for 230.10.10.10

数据流开始于：

vlc_video_on

验证（操作场景）

firepower# show capture
capture INSIDE type raw-data interface INSIDE [Buffer Full - 524156 bytes]    <-- Multicast packets on the egress interface
match ip host 192.168.103.60 host 230.10.10.10
capture OUTSIDE type raw-data trace interface OUTSIDE [Buffer Full - 524030 bytes]   <-- Multicast packets on the ingress interface
match ip host 192.168.103.60 host 230.10.10.10

防火墙的mroute表

firepower# show mroute
Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group,
       C - Connected, L - Local, I - Received Source Specific Host Report,
       P - Pruned, R - RP-bit set, F - Register flag, T - SPT-bit set,
       J - Join SPT
Timers: Uptime/Expires
Interface state: Interface, State

(*, 230.10.10.10), 00:00:34/never, RP 0.0.0.0, flags: SCJ
  Incoming interface: Null
  RPF nbr: 0.0.0.0
  Immediate Outgoing interface list:
    INSIDE, Forward, 00:00:34/never

(192.168.103.60, 230.10.10.10), 00:01:49/00:03:29, flags: SFJT
  Incoming interface: OUTSIDE
  RPF nbr: 192.168.103.60
  Inherited Outgoing interface list:
    INSIDE, Forward, 00:00:34/never        <-- The OIL shows an interface

firepower# show mfib 230.10.10.10
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
             AR - Activity Required, K - Keepalive
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second
Other counts: Total/RPF failed/Other drops
Interface Flags: A - Accept, F - Forward, NS - Negate Signalling
             IC - Internal Copy, NP - Not platform switched
             SP - Signal Present
Interface Counts: FS Pkt Count/PS Pkt Count

(*,230.10.10.10) Flags: C K
  Forwarding: 0/0/0/0, Other: 0/0/0
  INSIDE Flags: F NS
    Pkts: 0/0
(192.168.103.60,230.10.10.10) Flags: K
  Forwarding: 6373/0/1354/0, Other: 548/548/0      <-- There are multicast packets forwarded
  OUTSIDE Flags: A
  INSIDE Flags: F NS
    Pkts: 6373/6

mfib计数器：

firepower# show mfib count
IP Multicast Statistics
10 routes, 5 groups, 0.40 average sources per group
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kilobits per second
Other counts: Total/RPF failed/Other drops(OIF-null, rate-limit etc)
Group: 224.0.1.39
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
Group: 224.0.1.40
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
Group: 230.10.10.10
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
  Source: 192.168.103.60,
    Forwarding: 7763/0/1354/0, Other: 548/548/0   <-- There are multicast packets forwarded
  Tot. shown: Source count: 1, pkt count: 0
Group: 232.0.0.0/8
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
Group: 239.255.255.250
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
  Source: 192.168.1.50,
    Forwarding: 7/0/500/0, Other: 0/0/0
  Tot. shown: Source count: 1, pkt count: 0

IGMP 侦听

IGMP监听是交换机上使用的一种机制，用于防止组播泛洪。
交换机监控IGMP报告，以确定主机（接收器）的位置。
交换机监控IGMP查询，以确定路由器/防火墙（发送方）位于何处。
IGMP监听在大多数思科交换机上默认启用。有关详细信息，请查看相关的交换指南。以下是L3 Catalyst交换机的输出示例：

switch# show ip igmp snooping statistics

  Current number of Statistics entries    : 15
  Configured Statistics database limit    : 32000
  Configured Statistics database threshold: 25600
  Configured Statistics database limit    : Not exceeded
  Configured Statistics database threshold: Not exceeded

Snooping statistics for Vlan204
#channels: 3
#hosts   : 5

Source/Group                    Interface       Reporter        Uptime   Last-Join Last-Leave
0.0.0.0/230.10.10.10            Vl204:Gi1/48    192.168.1.50    2d13h        -     2d12h
0.0.0.0/230.10.10.10            Vl204:Gi1/48    192.168.1.97    2d13h    2d12h         -
0.0.0.0/230.10.10.10            Vl204:Gi2/1     192.168.1.50    2d10h    02:20:05  02:20:00
0.0.0.0/239.255.255.250         Vl204:Gi2/1     192.168.1.50    2d11h    02:20:05  02:20:00
0.0.0.0/239.255.255.250         Vl204:Gi2/1     192.168.2.50    2d14h    2d13h         -
0.0.0.0/239.255.255.250         Vl204:Gi2/1     192.168.6.50    2d13h        -     2d13h
0.0.0.0/224.0.1.40              Vl204:Gi2/26    192.168.2.1     2d14h    00:00:39  2d13h

Snooping statistics for Vlan206
#channels: 4
#hosts   : 3

Source/Group                    Interface       Reporter        Uptime   Last-Join Last-Leave
0.0.0.0/230.10.10.10            Vl206:Gi1/48    192.168.6.91    00:30:15 2d13h     2d13h
0.0.0.0/239.10.10.10            Vl206:Gi1/48    192.168.6.91    2d14h    2d13h         -
0.0.0.0/239.255.255.250         Vl206:Gi2/1     192.168.6.50    2d12h    00:52:49  00:52:45
0.0.0.0/224.0.1.40              Vl206:Gi2/26    192.168.6.1     00:20:10 2d13h     2d13h
0.0.0.0/230.10.10.10            Vl206:Gi2/26    192.168.6.1     2d13h    2d13h         -
0.0.0.0/230.10.10.10            Vl206:Gi2/26    192.168.6.91    2d13h        -     2d13h
0.0.0.0/239.10.10.10            Vl206:Gi2/26    192.168.6.1     2d14h    2d14h         -
0.0.0.0/239.10.10.10            Vl206:Gi2/26    192.168.6.91    2d14h        -     2d14h

任务3 - IGMP静态组与IGMP加入组

概述

	ip igmp static-group	ip igmp join-group
是否应用于FTD接口？	Yes	Yes
FTD是否吸引组播流？	是，PIM加入发送到上游设备。源或交汇点(RP)。仅当使用此命令的FTD是该接口上的PIM指定路由器(DR)时，才会出现这种情况。	是，PIM加入发送到上游设备。源或交汇点(RP)。仅当使用此命令的FTD是该接口上的PIM指定路由器(DR)时，才会出现这种情况。
FTD是否将组播流量从接口转发出去？	Yes	Yes
FTD是否消耗并回复组播流量	无	是，FTD将组播流传送到CPU，使用它，然后回复源。
CPU影响	最小，因为数据包未传送到CPU。	可以影响FTD CPU，因为属于组的每个组播数据包都会被传送到FTD CPU。

任务要求

请思考以下拓扑：

igmp_snooping_topology

在防火墙上启用以下捕获：

firepower# capture CAPI interface OUTSIDE trace match icmp host 192.168.103.62 any
firepower# capture CAPO interface INSIDE match icmp host 192.168.103.62 any

使用来自L3交换机的ICMP ping将组播流量发送到IP 230.11.11.11，并检查防火墙如何处理该流量。
在防火墙INSIDE接口上启用igmp static-group命令，并检查防火墙如何处理组播流(IP 230.11.11.11)。
在防火墙INSIDE接口上启用igmp static-group命令，并检查防火墙如何处理组播流(IP 230.11.11.11)。

解决方案

防火墙没有IP 230.11.11.11的任何路由：

firepower# show mroute

Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group,
       C - Connected, L - Local, I - Received Source Specific Host Report,
       P - Pruned, R - RP-bit set, F - Register flag, T - SPT-bit set,
       J - Join SPT
Timers: Uptime/Expires
Interface state: Interface, State

(*, 239.255.255.250), 00:43:21/never, RP 0.0.0.0, flags: SCJ
  Incoming interface: Null
  RPF nbr: 0.0.0.0
  Immediate Outgoing interface list:
    OUTSIDE, Forward, 00:05:41/never
    INSIDE, Forward, 00:43:21/never

测试组播的一种简单方法是使用ICMP ping工具。在这种情况下，从R2对组播IP地址230.11.11.11发起ping:

L3-Switch# ping 230.11.11.11 re 100
Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 230.11.11.11, timeout is 2 seconds:
...............................

在防火墙上，动态创建mroute，且OIL为空：

firepower# show mroute

Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group,
C - Connected, L - Local, I - Received Source Specific Host Report,
P - Pruned, R - RP-bit set, F - Register flag, T - SPT-bit set,
J - Join SPT
Timers: Uptime/Expires
Interface state: Interface, State

(192.168.103.62, 230.11.11.11), 00:02:33/00:00:56, flags: SPF  <-- The mroute is added
  Incoming interface: OUTSIDE
  RPF nbr: 192.168.103.62
 Outgoing interface list: Null     <-- The OIL is empty

防火墙上的捕获显示：

firepower# show capture
capture CAPI type raw-data trace interface OUTSIDE [Capturing - 1040 bytes]    <-- There are ICMP packets captured on ingress interface
match icmp host 192.168.103.62 any
capture CAPO type raw-data interface INSIDE [Capturing - 0 bytes]     <-- There are no ICMP packets on egress
match icmp host 192.168.103.62 any

防火墙会为每个ping创建连接，但会以静默方式丢弃数据包：

firepower# show log | include 230.11.11.11
May 17 2022 11:05:47: %FTD-7-609001: Built local-host identity:230.11.11.11       <-- A new connection is created
May 17 2022 11:05:47: %FTD-6-302020: Built inbound ICMP connection for faddr 192.168.1.99/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:47: %FTD-6-302020: Built inbound ICMP connection for faddr 192.168.103.62/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:49: %FTD-6-302021: Teardown ICMP connection for faddr 192.168.1.99/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:49: %FTD-6-302021: Teardown ICMP connection for faddr 192.168.103.62/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:49: %FTD-7-609002: Teardown local-host identity:230.11.11.11 duration 0:00:02  <-- The connection is closed
May 17 2022 11:05:51: %FTD-7-609001: Built local-host identity:230.11.11.11             <-- A new connection is created
May 17 2022 11:05:51: %FTD-6-302020: Built inbound ICMP connection for faddr 192.168.1.99/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:51: %FTD-6-302020: Built inbound ICMP connection for faddr 192.168.103.62/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:53: %FTD-6-302021: Teardown ICMP connection for faddr 192.168.1.99/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:53: %FTD-6-302021: Teardown ICMP connection for faddr 192.168.103.62/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:53: %FTD-7-609002: Teardown local-host identity:230.11.11.11 duration 0:00:02      <-- The connection is closed

注意：LINA ASP丢弃捕获不会显示丢弃的数据包

组播数据包丢弃的主要指示如下：

firepower# show mfib
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
             AR - Activity Required, K - Keepalive
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second
Other counts: Total/RPF failed/Other drops
Interface Flags: A - Accept, F - Forward, NS - Negate Signalling
             IC - Internal Copy, NP - Not platform switched
             SP - Signal Present
Interface Counts: FS Pkt Count/PS Pkt Count

(*,224.0.1.39) Flags: S K
  Forwarding: 0/0/0/0, Other: 0/0/0
(*,224.0.1.40) Flags: S K
  Forwarding: 0/0/0/0, Other: 0/0/0
(192.168.103.62,230.11.11.11) Flags: K         <-- The multicast stream
  Forwarding: 0/0/0/0, Other: 27/27/0          <-- The packets are dropped

igmp static-group

在FMC上配置静态IGMP组：

igmp_static_config

下面是后台部署的内容：

interface Port-channel1.205
 vlan 205
 nameif INSIDE
 cts manual
  propagate sgt preserve-untag
  policy static sgt disabled trusted
 security-level 0
 ip address 192.168.1.24 255.255.255.0
 igmp static-group 230.11.11.11        <-- IGMP static group is enabled on the interface

ping失败，但ICMP组播流量现在通过防火墙转发：

L3-Switch# ping 230.11.11.11 re 10000
Type escape sequence to abort.
Sending 10000, 100-byte ICMP Echos to 230.11.11.11, timeout is 2 seconds:
............................

firepower# show capture
capture CAPI type raw-data trace interface OUTSIDE [Capturing - 650 bytes]   <-- ICMP packets are captured on ingress interface
match icmp host 192.168.103.62 any
capture CAPO type raw-data interface INSIDE [Capturing - 670 bytes]    <-- ICMP packets are captured on egress interface
match icmp host 192.168.103.62 any

firepower# show capture CAPI
8 packets captured

1: 11:31:32.470541 192.168.103.62 > 230.11.11.11 icmp: echo request
2: 11:31:34.470358 192.168.103.62 > 230.11.11.11 icmp: echo request
3: 11:31:36.470831 192.168.103.62 > 230.11.11.11 icmp: echo request
4: 11:31:38.470785 192.168.103.62 > 230.11.11.11 icmp: echo request
...

firepower# show capture CAPO
11 packets captured

1: 11:31:32.470587 802.1Q vlan#205 P0 192.168.103.62 > 230.11.11.11 icmp: echo request
2: 11:31:34.470404 802.1Q vlan#205 P0 192.168.103.62 > 230.11.11.11 icmp: echo request
3: 11:31:36.470861 802.1Q vlan#205 P0 192.168.103.62 > 230.11.11.11 icmp: echo request
4: 11:31:38.470816 802.1Q vlan#205 P0 192.168.103.62 > 230.11.11.11 icmp: echo request

注意：数据包的跟踪显示不正确的输出(入口接口与出口相同。有关详细信息，请查看Cisco Bug ID CSCvm89673。

firepower# show capture CAPI packet-number 1 trace

1: 11:39:33.553987 192.168.103.62 > 230.11.11.11 icmp: echo request
Phase: 1
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 3172 ns
Config:
Additional Information:
MAC Access list

Phase: 2
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 3172 ns
Config:
Implicit Rule
Additional Information:
MAC Access list

Phase: 3
Type: ROUTE-LOOKUP
Subtype: No ECMP load balancing
Result: ALLOW
Elapsed time: 9760 ns
Config:
Additional Information:
Destination is locally connected. No ECMP load balancing.
Found next-hop 192.168.103.62 using egress ifc OUTSIDE(vrfid:0)

Phase: 4
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 5368 ns
Config:
Implicit Rule
Additional Information:

Phase: 5
Type: CONN-SETTINGS
Subtype:
Result: ALLOW
Elapsed time: 5368 ns
Config:
class-map class-default
match any
policy-map global_policy
class class-default
set connection advanced-options UM_STATIC_TCP_MAP
service-policy global_policy global
Additional Information:

Phase: 6
Type: NAT
Subtype: per-session
Result: ALLOW
Elapsed time: 5368 ns
Config:
Additional Information:

Phase: 7
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Elapsed time: 5368 ns
Config:
Additional Information:

Phase: 8
Type: CLUSTER-REDIRECT
Subtype: cluster-redirect
Result: ALLOW
Elapsed time: 31720 ns
Config:
Additional Information:

Phase: 9
Type: INSPECT
Subtype: np-inspect
Result: ALLOW
Elapsed time: 488 ns
Config:
class-map inspection_default
match default-inspection-traffic
policy-map global_policy
class inspection_default
inspect icmp
service-policy global_policy global
Additional Information:

Phase: 10
Type: INSPECT
Subtype: np-inspect
Result: ALLOW
Elapsed time: 2440 ns
Config:
Additional Information:

Phase: 11
Type: MULTICAST    <-- The packet is multicast
Subtype:
Result: ALLOW
Elapsed time: 976 ns
Config:
Additional Information:

Phase: 12
Type: FLOW-CREATION    <-- A new flow is created
Subtype:
Result: ALLOW
Elapsed time: 56120 ns
Config:
Additional Information:
New flow created with id 5690, packet dispatched to next module

Phase: 13
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 10248 ns
Config:
Additional Information:
MAC Access list

Result:
input-interface: OUTSIDE(vrfid:0)
input-status: up
input-line-status: up
output-interface: OUTSIDE(vrfid:0)
output-status: up
output-line-status: up
Action: allow       <-- The packet is allowed
Time Taken: 139568 ns

提示：可以从源主机使用超时0执行ping操作，还可以检查防火墙mfib计数器：

L3-Switch# ping 230.11.11.11 re 500 timeout 0
Type escape sequence to abort.
Sending 1000, 100-byte ICMP Echos to 230.11.11.11, timeout is 0 seconds:
......................................................................
......................................................................
......................................................................
....................

firepower# clear mfib counters
firepower# !ping from the source host. 

firepower# show mfib 230.11.11.11
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
AR - Activity Required, K - Keepalive
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second
Other counts: Total/RPF failed/Other drops
Interface Flags: A - Accept, F - Forward, NS - Negate Signalling
IC - Internal Copy, NP - Not platform switched
SP - Signal Present
Interface Counts: FS Pkt Count/PS Pkt Count

(*,230.11.11.11) Flags: C K
  Forwarding: 0/0/0/0, Other: 0/0/0
  INSIDE Flags: F NS
    Pkts: 0/0
(192.168.103.62,230.11.11.11) Flags: K
  Forwarding: 500/0/100/0, Other: 0/0/0    <-- 500 multicast packets forwarded. The average size of each packet is 100 Bytes
  OUTSIDE Flags: A
  INSIDE Flags: F NS
    Pkts: 500/0

igmp join-group

在FMC远程上，配置先前配置的静态组配置并配置IGMP加入组：

igmp_join_config

igmp_join_topology

已部署的配置：

firepower# show run interface Port-channel1.205
!
interface Port-channel1.205
vlan 205
nameif INSIDE
cts manual
propagate sgt preserve-untag
policy static sgt disabled trusted
security-level 0
ip address 192.168.1.24 255.255.255.0
igmp join-group 230.11.11.11       <-- The interface joined the multicast group

IGMP组：

firepower# show igmp group
IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter
230.11.11.11 INSIDE 00:30:43 never 192.168.1.24   <-- The group is enabled on the interface

从源主机，尝试对230.11.11.11 IP执行第一个ICMP组播测试：

L3-Switch# ping 230.11.11.11 repeat 10
Type escape sequence to abort.
Sending 10, 100-byte ICMP Echos to 230.11.11.11, timeout is 2 seconds:

Reply to request 0 from 192.168.1.24, 12 ms
Reply to request 1 from 192.168.1.24, 8 ms
Reply to request 2 from 192.168.1.24, 8 ms
Reply to request 3 from 192.168.1.24, 8 ms
Reply to request 4 from 192.168.1.24, 8 ms
Reply to request 5 from 192.168.1.24, 12 ms
Reply to request 6 from 192.168.1.24, 8 ms
Reply to request 7 from 192.168.1.24, 8 ms
Reply to request 8 from 192.168.1.24, 8 ms
Reply to request 9 from 192.168.1.24, 8 ms

注意：如果您没有看到所有回复，请检查Cisco Bug ID CSCvm90069。

任务4 — 配置IGMP末节组播路由

stub_topology

在FTD上配置末节组播路由，以便将INSIDE接口上收到的IGMP成员身份报告消息转发到OUTSIDE接口。

解决方案

已部署的配置：

firepower# show run multicast-routing
multicast-routing               <-- Multicast routing is enabled
firepower# show run interface Port-channel1.205
!
interface Port-channel1.205
 vlan 205
 nameif INSIDE
 cts manual
  propagate sgt preserve-untag
  policy static sgt disabled trusted
 security-level 0
 ip address 192.168.1.24 255.255.255.0
 igmp forward interface OUTSIDE        <-- The interface does stub multicast routing

确认

在FTD上启用捕获：

firepower# capture CAPI interface INSIDE trace match igmp any host 230.10.10.10
firepower# capture CAPO interface OUTSIDE match igmp any host 230.10.10.10

确认

要强制IGMP成员报告，您可以使用类似VLC的应用程序：

vlc_play_ip_stream

FTD代理IGMP数据包：

firepower# show capture
capture CAPI type raw-data trace interface INSIDE [Capturing - 66 bytes]  <-- IGMP packets captured on ingress
match igmp any host 230.10.10.10
capture CAPO type raw-data interface OUTSIDE [Capturing - 62 bytes]   <-- IGMP packets captured on egress
match igmp any host 230.10.10.10

FTD更改源IP:

firepower# show capture CAPI

1 packet captured

   1: 12:21:12.820483 802.1Q vlan#205 P6 192.168.1.50 > 230.10.10.10 ip-proto-2, length 8    <-- The source IP of the packet on ingress interface
1 packet shown
firepower# show capture CAPO

1 packet captured

   1: 12:21:12.820743 192.168.103.91 > 230.10.10.10 ip-proto-2, length 8  <-- The source IP of the packet on egress interface
1 packet shown

如果检查Wireshark中的pcap，可以看到数据包完全由防火墙重新生成（IP标识更改）。

在FTD上创建组条目：

firepower# show igmp group
IGMP Connected Group Membership
Group Address    Interface            Uptime    Expires   Last Reporter
230.10.10.10     INSIDE               00:15:22  00:03:28  192.168.1.50     <-- IGMP group is enabled on the ingress interface
239.255.255.250  INSIDE               00:15:27  00:03:29  192.168.1.50

FTD防火墙创建2个控制平面连接：

firepower# show conn all address 230.10.10.10
9 in use, 28 most used
Inspect Snort:
preserve-connection: 0 enabled, 0 in effect, 0 most enabled, 0 most in effect
IGMP INSIDE 192.168.1.50 NP Identity Ifc 230.10.10.10, idle 0:00:09, bytes 8, flags          <-- Connection terminated on the ingress interface
IGMP OUTSIDE 230.10.10.10 NP Identity Ifc 192.168.103.91, idle 0:00:09, bytes 8, flags       <-- Connection terminated on the egress interface

第一个数据包的跟踪：

firepower# show capture CAPI packet-number 1 trace

6 packets captured

1: 12:21:12.820483 802.1Q vlan#205 P6 192.168.1.50 > 230.10.10.10 ip-proto-2, length 8   <-- The first packet of the flow
Phase: 1
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 5124 ns
Config:
Additional Information:
MAC Access list

Phase: 2
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 5124 ns
Config:
Implicit Rule
Additional Information:
MAC Access list

Phase: 3
Type: ROUTE-LOOKUP
Subtype: No ECMP load balancing
Result: ALLOW
Elapsed time: 7808 ns
Config:
Additional Information:
Destination is locally connected. No ECMP load balancing.
Found next-hop 192.168.1.50 using egress ifc INSIDE(vrfid:0)

Phase: 4
Type: CLUSTER-DROP-ON-SLAVE
Subtype: cluster-drop-on-slave
Result: ALLOW
Elapsed time: 5368 ns
Config:
Additional Information:

Phase: 5
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 5368 ns
Config:
Implicit Rule
Additional Information:

Phase: 6
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Elapsed time: 5368 ns
Config:
Additional Information:

Phase: 7
Type: NAT
Subtype: per-session
Result: ALLOW
Elapsed time: 5368 ns
Config:
Additional Information:

Phase: 8
Type: CLUSTER-REDIRECT
Subtype: cluster-redirect
Result: ALLOW
Elapsed time: 40504 ns
Config:
Additional Information:

Phase: 9
Type: MULTICAST        <-- The packet is multicast
Subtype:
Result: ALLOW
Elapsed time: 976 ns
Config:
Additional Information:

Phase: 10
Type: FLOW-CREATION       <-- A new flow is created
Subtype:
Result: ALLOW
Elapsed time: 17568 ns
Config:
Additional Information:
New flow created with id 5945, packet dispatched to next module

Phase: 11
Type: FLOW-CREATION      <-- A second flow is created
Subtype:
Result: ALLOW
Elapsed time: 39528 ns
Config:
Additional Information:
New flow created with id 5946, packet dispatched to next module

Phase: 12
Type: NEXTHOP-LOOKUP-FROM-OUTPUT-ROUTE-LOOKUP
Subtype: Lookup Nexthop on interface
Result: ALLOW
Elapsed time: 6344 ns
Config:
Additional Information:
Found next-hop 230.10.10.10 using egress ifc OUTSIDE(vrfid:0)

Phase: 13
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 9760 ns
Config:
Additional Information:
MAC Access list

Result:
input-interface: INSIDE(vrfid:0)
input-status: up
input-line-status: up
output-interface: INSIDE(vrfid:0)
output-status: up
output-line-status: up
Action: allow
Time Taken: 154208 ns

已知问题

过滤目标区域上的组播流量

您不能为匹配组播流量的访问控制策略规则指定目标安全区域：

acp_misconfig

FMC用户指南中也介绍了以下内容：

fmc_config_guide

当超过IGMP接口限制时，防火墙会拒绝IGMP报告

默认情况下，防火墙允许接口上最多有500个当前活动联接（报告）。如果超过此阈值，防火墙会忽略来自组播接收器的其他传入IGMP报告。

要检查IGMP限制和活动联接，请运行命令show igmp interface nameif:

asa# show igmp interface inside
inside is up, line protocol is up
  Internet address is 10.10.10.1/24
  IGMP is enabled on interface
  Current IGMP version is 2
  IGMP query interval is 125 seconds
  IGMP querier timeout is 255 seconds
  IGMP max query response time is 10 seconds
  Last member query response interval is 1 seconds
  Inbound IGMP access group is:   
  IGMP limit is 500, currently active joins: 500
  Cumulative IGMP activity: 0 joins, 0 leaves
  IGMP querying router is 10.10.10.1 (this system)

IGMP debug命令debug igmp显示以下输出：

asa# debug igmp
Apr 20 2023 09:37:10: %ASA-7-711001: IGMP: Group 230.1.2.3 limit denied on inside

软件版本中修复了Cisco Bug ID CSCvw60976 允许用户为每个接口配置最多5000个组。

防火墙忽略232.x.x.x/8地址范围的IGMP报告

232.x.x.x/8地址范围用于源特定组播(SSM)。防火墙不支持PIM源特定组播(SSM)功能和相关配置。

IGMP debug命令debug igmp显示以下输出：

asa# debug igmp
Apr 20 2023 09:37:10: %ASA-7-711001: IGMP: Received v2 Report on inside from 10.10.10.11 for 232.179.89.253
Apr 20 2023 09:37:10: %ASA-7-711001: IGMP: group_db: add new group 232.179.89.253 on inside
Apr 20 2023 09:37:10: %ASA-7-711001: IGMP: Exclude report on inside ignored for SSM group 232.179.89.253

Cisco Bug ID CSCsr53916 跟踪增强功能以支持SSM范围。

Firepower威胁防御IGMP和组播基础故障排除

下载选项

非歧视性语言

关于此翻译

目录

简介

先决条件

要求

使用的组件

背景信息

配置

IGMP基础知识

任务1 — 控制平面组播流量

任务2 — 配置基本组播

IGMP 侦听

任务3 - IGMP静态组与IGMP加入组

igmp static-group

igmp join-group

任务4 — 配置IGMP末节组播路由

已知问题

过滤目标区域上的组播流量

当超过IGMP接口限制时，防火墙会拒绝IGMP报告

防火墙忽略232.x.x.x/8地址范围的IGMP报告

相关信息

修订历史记录

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