How is ICMP redirect enabled? RRS feed

  • Question

  • A 2012 server is not adding routes to the routing table.  The Sonicwall is definitely sending ICMP redirect packets and the firewall allows ICMP redirects.  In fact setting the firewall to allow doesn't fix it.

    Performance monitor even shows ICMP redirect packets arriving on the server.

    So why isn't the route being added to the route table?

    Friday, October 11, 2013 7:56 PM

All replies

  • Hi,

    Windows NT Specifics:
    A host route learned by means of an ICMP Redirect will be added to the route table for 10 minutes, after which time it is removed and must be relearned through another ICMP Redirect.

    This is described in KB 195686

    Explanation of ICMP Redirect Behavior

    Hope this helps.

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    • Proposed as answer by cguan Monday, October 14, 2013 9:53 AM
    • Marked as answer by Daniel JiSunModerator Thursday, October 17, 2013 8:24 AM
    • Unmarked as answer by dga_1 Tuesday, November 5, 2013 6:17 PM
    • Unproposed as answer by dga_1 Tuesday, November 5, 2013 6:17 PM
    Monday, October 14, 2013 9:22 AM
  • I article says that ICMP redirects are supported.  My question is why doesn't it work?

    I see ICMP redirect being sent to the server but I don't see the routes listed in "route print".  Also a packet capture shows the packets going to the default router and it sending it to the other router.

    Has anybody actually seen ICMP redirects actually work?

    Tuesday, November 5, 2013 6:26 PM
  • I have upgraded to Server 2012 R2 now.  ICMP redirects DO work provided you allow the ICMP redirect through the Firewall.

    HOWEVER, the problem is that these routes do NOT show in the "route print" command.  This is bad because there may be a problem and there are routes that are being used by the server that are not published.

    Does anybody know how to list routes created by the ICMP redirects?

    Monday, April 28, 2014 3:30 PM
  • check out this link:

    Try to install Routing and Remote Access and view the routing table(using this option), check if you will have the ICMP redirect listed on it.

    Because for command prompt there is no protocol column listed.

    check out this link: <View the Routing Table>

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    Tuesday, April 29, 2014 7:30 AM