Restart IOS DHCP server after a change in DHCP pools

I've stumbled across an interesting problem recently:

  • I've added a Linux box to my home network;
  • It used my Cisco router to get a dynamic DHCP address;
  • I've inspected the DHCP bindings on the Cisco router to find the new MAC address and configured a host DHCP pool as I'm using the Linux box as a server;
  • Even after multiple configuration changes, the IOS would fail to use the host DHCP pool.

The only solution I've found was to restart the IOS DHCP server with the no service dhcp followed by service dhcp configuration commands. Obviously, you lose all DHCP bindings when you restart the DHCP server (which could be a problem if you use conflict logging) unless you've configured the router to store them in an external file.

1 comment:

  1. I've always issued a "clear ip dhcp binding *ip-address*" before setting up the host pool, for this very reason.

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Ivan Pepelnjak, CCIE#1354, is the chief technology advisor for NIL Data Communications. He has been designing and implementing large-scale data communications networks as well as teaching and writing books about advanced technologies since 1990. See his full profile, contact him or follow @ioshints on Twitter.