This example provides a scenario in which packet trace is used to troubleshoot packet drops for a NAT configuration on a Cisco
ASR 1006 Router. This example shows how you can effectively utilize the level of detail provided by the Packet-Trace feature
to gather information about an issue, isolate the issue, and then find a solution.
In this scenario, you can detect that there are issues, but are not sure where to start troubleshooting. You should, therefore,
consider accessing the Packet-Trace summary for a number of incoming packets.
Router# debug platform condition ingress
Router# debug platform packet-trace packet 2048 summary-only
Router# debug platform condition start
Router# debug platform condition stop
Router# show platform packet-trace summary
Pkt Input Output State Reason
0 Gi0/0/0 Gi0/0/0 DROP 402 (NoStatsUpdate)
1 internal0/0/rp:0 internal0/0/rp:0 PUNT 21 (RP<->QFP keepalive)
2 internal0/0/recycle:0 Gi0/0/0 FWD
The output shows that packets are dropped due to NAT configuration on Gigabit Ethernet interface 0/0/0, which enables you
to understand that an issue is occurring on a specific interface. Using this information, you can limit which packets to trace,
reduce the number of packets for data capture, and increase the level of inspection.
Router# debug platform packet-trace packet 256
Router# debug platform packet-trace punt
Router# debug platform condition interface Gi0/0/0
Router# debug platform condition start
Router# debug platform condition stop
Router# show platform packet-trace summary
Router# show platform packet-trace 15
Packet: 15 CBUG ID: 238
Summary
Input : GigabitEthernet0/0/0
Output : internal0/0/rp:1
State : PUNT 55 (For-us control)
Timestamp
Start : 1166288346725 ns (06/06/2016 09:09:42.202734 UTC)
Stop : 1166288383210 ns (06/06/2016 09:09:42.202770 UTC)
Path Trace
Feature: IPV4
Input : GigabitEthernet0/0/0
Output : <unknown>
Source : 10.64.68.3
Destination : 224.0.0.102
Protocol : 17 (UDP)
SrcPort : 1985
DstPort : 1985
IOSd Path Flow: Packet: 15 CBUG ID: 238
Feature: INFRA
Pkt Direction: IN
Packet Rcvd From CPP
Feature: IP
Pkt Direction: IN
Source : 10.64.68.122
Destination : 10.64.68.255
Feature: IP
Pkt Direction: IN
Packet Enqueued in IP layer
Source : 10.64.68.122
Destination : 10.64.68.255
Interface : GigabitEthernet0/0/0
Feature: UDP
Pkt Direction: IN
src : 10.64.68.122(1053)
dst : 10.64.68.255(1947)
length : 48
Router#show platform packet-trace packet 10
Packet: 10 CBUG ID: 10
Summary
Input : GigabitEthernet0/0/0
Output : internal0/0/rp:0
State : PUNT 55 (For-us control)
Timestamp
Start : 274777907351 ns (01/10/2020 10:56:47.918494 UTC)
Stop : 274777922664 ns (01/10/2020 10:56:47.918509 UTC)
Path Trace
Feature: IPV4(Input)
Input : GigabitEthernet0/0/0
Output : <unknown>
Source : 10.78.106.2
Destination : 224.0.0.102
Protocol : 17 (UDP)
SrcPort : 1985
DstPort : 1985
IOSd Path Flow: Packet: 10 CBUG ID: 10
Feature: INFRA
Pkt Direction: IN
Packet Rcvd From DATAPLANE
Feature: IP
Pkt Direction: IN
Packet Enqueued in IP layer
Source : 10.78.106.2
Destination : 224.0.0.102
Interface : GigabitEthernet0/0/0
Feature: UDP
Pkt Direction: IN DROP
Pkt : DROPPED
UDP: Discarding silently
src : 881 10.78.106.2(1985)
dst : 224.0.0.102(1985)
length : 60
Router#show platform packet-trace packet 12
Packet: 12 CBUG ID: 767
Summary
Input : GigabitEthernet3
Output : internal0/0/rp:0
State : PUNT 11 (For-us data)
Timestamp
Start : 16120990774814 ns (01/20/2020 12:38:02.816435 UTC)
Stop : 16120990801840 ns (01/20/2020 12:38:02.816462 UTC)
Path Trace
Feature: IPV4(Input)
Input : GigabitEthernet3
Output : <unknown>
Source : 12.1.1.1
Destination : 12.1.1.2
Protocol : 6 (TCP)
SrcPort : 46593
DstPort : 23
IOSd Path Flow: Packet: 12 CBUG ID: 767
Feature: INFRA
Pkt Direction: IN
Packet Rcvd From DATAPLANE
Feature: IP
Pkt Direction: IN
Packet Enqueued in IP layer
Source : 12.1.1.1
Destination : 12.1.1.2
Interface : GigabitEthernet3
Feature: IP
Pkt Direction: IN
FORWARDEDTo transport layer
Source : 12.1.1.1
Destination : 12.1.1.2
Interface : GigabitEthernet3
Feature: TCP
Pkt Direction: IN
tcp0: I NoTCB 12.1.1.1:46593 12.1.1.2:23 seq 1925377975 OPTS 4 SYN WIN 4128
Router# show platform packet-trace summary
Pkt Input Output State Reason
0 INJ.2 Gi1 FWD
1 Gi1 internal0/0/rp:0 PUNT 11 (For-us data)
2 INJ.2 Gi1 FWD
3 Gi1 internal0/0/rp:0 PUNT 11 (For-us data)
4 INJ.2 Gi1 FWD
5 INJ.2 Gi1 FWD
6 Gi1 internal0/0/rp:0 PUNT 11 (For-us data)
7 Gi1 internal0/0/rp:0 PUNT 11 (For-us data)
8 Gi1 internal0/0/rp:0 PUNT 11 (For-us data)
9 Gi1 internal0/0/rp:0 PUNT 11 (For-us data)
10 INJ.2 Gi1 FWD
11 INJ.2 Gi1 FWD
12 INJ.2 Gi1 FWD
13 Gi1 internal0/0/rp:0 PUNT 11 (For-us data)
14 Gi1 internal0/0/rp:0 PUNT 11 (For-us data)
15 Gi1 internal0/0/rp:0 PUNT 11 (For-us data)
16 INJ.2 Gi1 FWD
The following example displays the packet trace data statistics.
Router#show platform packet-trace statistics
Packets Summary
Matched 3
Traced 3
Packets Received
Ingress 0
Inject 0
Packets Processed
Forward 0
Punt 3
Count Code Cause
3 56 RP injected for-us control
Drop 0
Consume 0
PKT_DIR_IN
Dropped Consumed Forwarded
INFRA 0 0 0
TCP 0 0 0
UDP 0 0 0
IP 0 0 0
IPV6 0 0 0
ARP 0 0 0
PKT_DIR_OUT
Dropped Consumed Forwarded
INFRA 0 0 0
TCP 0 0 0
UDP 0 0 0
IP 0 0 0
IPV6 0 0 0
ARP 0 0 0
The following example displays packets that are injected and punted to the forwarding processor from the control plane.
Router#debug platform condition ipv4 10.118.74.53/32 both
Router#Router#debug platform condition start
Router#debug platform packet-trace packet 200
Packet count rounded up from 200 to 256
Router#show platform packet-tracer packet 0
show plat pack pa 0
Packet: 0 CBUG ID: 674
Summary
Input : GigabitEthernet1
Output : internal0/0/rp:0
State : PUNT 11 (For-us data)
Timestamp
Start : 17756544435656 ns (06/29/2020 18:19:17.326313 UTC)
Stop : 17756544469451 ns (06/29/2020 18:19:17.326346 UTC)
Path Trace
Feature: IPV4(Input)
Input : GigabitEthernet1
Output : <unknown>
Source : 10.118.74.53
Destination : 172.18.124.38
Protocol : 17 (UDP)
SrcPort : 2640
DstPort : 500
IOSd Path Flow: Packet: 0 CBUG ID: 674
Feature: INFRA
Pkt Direction: IN
Packet Rcvd From DATAPLANE
Feature: IP
Pkt Direction: IN
Packet Enqueued in IP layer
Source : 10.118.74.53
Destination : 172.18.124.38
Interface : GigabitEthernet1
Feature: IP
Pkt Direction: IN
FORWARDED To transport layer
Source : 10.118.74.53
Destination : 172.18.124.38
Interface : GigabitEthernet1
Feature: UDP
Pkt Direction: IN
DROPPED
UDP: Checksum error: dropping
Source : 10.118.74.53(2640)
Destination : 172.18.124.38(500)
Router#show platform packet-tracer packet 2
Packet: 2 CBUG ID: 2
IOSd Path Flow:
Feature: TCP
Pkt Direction: OUTtcp0: O SYNRCVD 172.18.124.38:22 172.18.124.55:52774 seq 3052140910 OPTS 4 ACK 2346709419 SYN WIN 4128
Feature: TCP
Pkt Direction: OUT
FORWARDED
TCP: Connection is in SYNRCVD state
ACK : 2346709419
SEQ : 3052140910
Source : 172.18.124.38(22)
Destination : 172.18.124.55(52774)
Feature: IP
Pkt Direction: OUTRoute out the generated packet.srcaddr: 172.18.124.38, dstaddr: 172.18.124.55
Feature: IP
Pkt Direction: OUTInject and forward successful srcaddr: 172.18.124.38, dstaddr: 172.18.124.55
Feature: TCP
Pkt Direction: OUTtcp0: O SYNRCVD 172.18.124.38:22 172.18.124.55:52774 seq 3052140910 OPTS 4 ACK 2346709419 SYN WIN 4128
Summary
Input : INJ.2
Output : GigabitEthernet1
State : FWD
Timestamp
Start : 490928006866 ns (06/29/2020 13:31:30.807879 UTC)
Stop : 490928038567 ns (06/29/2020 13:31:30.807911 UTC)
Path Trace
Feature: IPV4(Input)
Input : internal0/0/rp:0
Output : <unknown>
Source : 172.18.124.38
Destination : 172.18.124.55
Protocol : 6 (TCP)
SrcPort : 22
DstPort : 52774
Feature: IPSec
Result : IPSEC_RESULT_DENY
Action : SEND_CLEAR
SA Handle : 0
Peer Addr : 55.124.18.172
Local Addr: 38.124.18.172
Router#