在Cisco IOS?/IOS-XE路由器上配置TCP拦截

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已更新: 2018 年 2 月 6 日

文档 ID:200792

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简介

本文档介绍在Cisco IOS®/IOS-XE路由器上启用思科传输控制协议(TCP)拦截功能的要求。要保护TCP服务器免受TCP同步(SYN)泛洪攻击（一种拒绝服务攻击），需要使用TCP拦截。

先决条件

要求

本文档没有任何特定的要求。

使用的组件

本文档不限于特定的软件和硬件版本。

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。

问题

您无法在ISR G1/G2/G3和ASR1k路由器上配置“ip tcp intercept”。您可以在此处看到日志：

对于ISR G1路由器

Router#show ver

Cisco IOS® Software, 2800 Software (C2800NM-IPBASEK9-M), Version 15.1(4)M12a, RELEASE SOFTWARE (fc1)
Router uptime is 14 minutes
System returned to ROM by reload at 07:45:56 UTC Tue Nov 1 2016
System image file is "flash:c2800nm-ipbasek9-mz.151-4.M12a(1).bin"


Last reload type: Normal Reload


<omitted>

Cisco 2811 (revision 1.0) with 512000K/12288K bytes of memory.
Processor board ID FHK1404F3U8
2 FastEthernet interfaces
1 Channelized E1/PRI port
DRAM configuration is 64 bits wide with parity enabled.
239K bytes of non-volatile configuration memory.
250368K bytes of ATA CompactFlash (Read/Write)

 

License Info:


License UDI:

-------------------------------------------------
Device#   PID                 SN
-------------------------------------------------
*0       CISCO2811             FHK1404F3U8   

Configuration register is 0x2102

 

Router#    config t

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)#ip tcp ?
  RST-count           Configure RST throttle count
  async-mobility      Configure async-mobility
  chunk-size          TCP chunk size
  ecn                 Enable Explicit Congestion Notification
  mss                 TCP initial maximum segment size
  path-mtu-discovery  Enable path-MTU discovery on new TCP connections
  queuemax            Maximum queue of outgoing TCP packets
  selective-ack       Enable TCP selective-ACK
  synwait-time        Set time to wait on new TCP connections
  timestamp           Enable TCP timestamp option
  window-size         TCP window size

对于ISR G2路由器

Router#show ver

Cisco IOS® Software, C1900 Software (C1900-UNIVERSALK9-M), Version 15.4(3)M4, RELEASE SOFTWARE (fc1)

<omitted>

Router uptime is 1 minute
System returned to ROM by reload at 10:28:40 UTC Mon Oct 31 2016
System image file is "flash:c1900-universalk9-mz.SPA.154-3.M4.bin"
Last reload type: Normal Reload
Last reload reason: Reload Command

<omitted>

Cisco CISCO1941/K9 (revision 1.0) with 2543552K/77824K bytes of memory.
Processor board ID FHK141571QW
4 FastEthernet interfaces

<omitted>

Technology Package License Information for Module:'c1900'

 
------------------------------------------------------------------------
Technology    Technology-package                  Technology-package
              Current              Type           Next reboot 
------------------------------------------------------------------------
ipbase        ipbasek9             Permanent      ipbasek9
security      securityk9           RightToUse     securityk9
data          None                 None           None          
NtwkEss       None                 None           None


Configuration register is 0x2102


Router#    config t

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)#ip tcp ?
  RST-count           Configure RST throttle count
  async-mobility      Configure async-mobility
  chunk-size          TCP chunk size
  ecn                 Enable Explicit Congestion Notification
  keepalive           Configure TCP Keepalive parameters
  mss                 TCP initial maximum segment size
  path-mtu-discovery  Enable path-MTU discovery on new TCP connections
  queuemax            Maximum queue of outgoing TCP packets
  selective-ack       Enable TCP selective-ACK
  synwait-time        Set time to wait on new TCP connections
  timestamp           Enable TCP timestamp option
  window-size         TCP window size

对于ISR G3路由器

Router#sh ver

Cisco IOS® XE Software, Version 03.15.02.S - Standard Support Release
Cisco IOS® Software, ISR Software (X86_64_LINUX_IOS® D-UNIVERSALK9-M), Version 15.5(2)S2, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2015 by Cisco Systems, Inc.
Compiled Fri 16-Oct-15 18:00 by mcpre

<omitted>

Router uptime is 7 minutes
Uptime for this control processor is 8 minutes
System returned to ROM by reload
System image file is "bootflash:isr4300-universalk9.03.15.02.S.155-2.S2-std.SPA.bin"
Last reload reason: Reload Command

<omitted>

Technology Package License Information: 

-----------------------------------------------------------------
Technology    Technology-package           Technology-package
              Current       Type           Next reboot 
------------------------------------------------------------------
appx             None             None             None            
uc               uck9             Permanent        uck9
security         securityk9       EvalRightToUse   securityk9
ipbase           ipbasek9         Permanent        ipbasek9

 

cisco ISR4331/K9 (1RU) processor with 1665776K/6147K bytes of memory.
Processor board ID FDO2012A0AT
3 Gigabit Ethernet interfaces
32768K bytes of non-volatile configuration memory.
4194304K bytes of physical memory.
3223551K bytes of flash memory at bootflash:.


Configuration register is 0x2102

 

Router#    config t

Enter configuration commands, one per line.  End with CNTL/Z.


Router(config)#ip tcp ?
  RST-count           Configure RST throttle count
  async-mobility      Configure async-mobility
  chunk-size          TCP chunk size
  ecn                 Enable Explicit Congestion Notification
  keepalive           Configure TCP Keepalive parameters
  mss                 TCP initial maximum segment size
  path-mtu-discovery  Enable path-MTU discovery on new TCP connections
  queuemax            Maximum queue of outgoing TCP packets
  selective-ack       Enable TCP selective-ACK
  synwait-time        Set time to wait on new TCP connections
  timestamp           Enable TCP timestamp option
  window-size         TCP window size

对于ASR1k路由器

Router#show version

Cisco IOS® XE Software, Version 03.16.01a.S - Extended Support Release
Cisco IOS® Software, ASR1000 Software (X86_64_LINUX_IOSD-UNIVERSAL-M), Version 15.5(3)S1a, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2015 by Cisco Systems, Inc.
Compiled Wed 04-Nov-15 13:57 by mcpre

<omitted>

Router uptime is 1 minute
Uptime for this control processor is 2 minutes
System returned to ROM by reload
System image file is "bootflash:asr1001x-universal.03.16.01a.S.155-3.S1a-ext.SPA.bin"
Last reload reason: PowerOn

License Level: ipbase
License Type: Permanent
Next reload license Level: ipbase

cisco ASR1001-X (1NG) processor (revision 1NG) with 3753592K/6147K bytes of memory.
Processor board ID FXS1925Q33T
6 Gigabit Ethernet interfaces
2 Ten Gigabit Ethernet interfaces
32768K bytes of non-volatile configuration memory.
8388608K bytes of physical memory.
6684671K bytes of eUSB flash at bootflash:
 

Configuration register is 0x2102
Router#config t
Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)#ip tcp ?
  RST-count           Configure RST throttle count
  async-mobility      Configure async-mobility
  chunk-size          TCP chunk size
  ecn                 Enable Explicit Congestion Notification
  keepalive           Configure TCP Keepalive parameters
  mss                 TCP initial maximum segment size
  path-mtu-discovery  Enable path-MTU discovery on new TCP connections
  queuemax            Maximum queue of outgoing TCP packets
  selective-ack       Enable TCP selective-ACK
  synwait-time        Set time to wait on new TCP connections
  timestamp           Enable TCP timestamp option
  window-size         TCP window size

解决方案

要启用TCP拦截功能，您需要：

ISR G1路由器上的entbase功能集的最小值
ISRG2和G3系列路由器上的Appxk9/Datak9
ASR1k系列路由器上的最低AdvipServices许可证

在平台上启用所需的许可证后，您可以配置相同的许可证：

Router(config)#ip tcp ?
  RST-count           Configure RST throttle count
  async-mobility      Configure async-mobility
  chunk-size          TCP chunk size
  ecn                 Enable Explicit Congestion Notification
  intercept           Enable TCP intercepting
  keepalive           Configure TCP Keepalive parameters
  mss                 TCP initial maximum segment size
  path-mtu-discovery  Enable path-MTU discovery on new TCP connections
  queuemax            Maximum queue of outgoing TCP packets
  selective-ack       Enable TCP selective-ACK
  synwait-time        Set time to wait on new TCP connections
  timestamp           Enable TCP timestamp option
  window-size         TCP window size

验证

当前没有可用于此配置的验证过程。

故障排除

目前没有针对此配置的故障排除信息。

在Cisco IOS?/IOS-XE路由器上配置TCP拦截

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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

问题

对于ISR G1路由器

对于ISR G2路由器

对于ISR G3路由器

对于ASR1k路由器

解决方案

验证

故障排除

相关信息

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