DHCP-based static routes

If you have configured your router as a DHCP client, you can use the default router option received in a DHCP reply as the next-hop for a static route. For example:

ip route 10.0.0.0 255.0.0.0 dhcp

You could use this functionality in scenarios where your core network uses DHCP (for example, in metropolitan networks using layer-2 Ethernet transport from an ISP), but your router needs a different default route.

You can also use this feature to change the administrative distance of the DHCP-based default route (or you could use the ip dhcp-client default-router distance value configuration command that one of the readers described in a comment to a previous DHCP-related post).

Any other good ideas where this might come handy? Post them as comments ...

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4 comments:

  1. Anonymous 22 August 2007 05:02
    I hope IOS 12.4 should be able to support?
  2. Ivan Pepelnjak 22 August 2007 06:38
    According to CCO available in IOS release 12.3(8)T and 12.3(9).
  3. Anonymous 11 June 2009 21:02
    This is great option to have but the problem for me is after a DHCP address renew event. IOS doesn't seems to use the newly assigned gateway (my ISP use /30 address so the gateway always changes depending which /30 block you get from DHCP).
  4. jhosbell 17 December 2013 01:02
    Hi everyone,

    If I have two ISP with DHCP(that means two default routes) and I want to make one of those the Active ISP and another being the backup ISP, how can I achive that?

    Because "ip dhcp-client default-router distance value" changes the metric of ALL dhcp routes, so they both have the same metric, additionally using route-maps you cannot use "set ip next-hop verify-availability" because it is dynamic so you have to use set interface, and there is no Verify-availability for that.

    Any ideas?
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