Enabling DHCP when the WAN is down...

Unanswered Question

Hi there,


I am not sure whether it is possible or not. My DHCP server is located in the datacenter, accessible for clients over the WAN. I am looking for a solution where, if my WAN is down the clients/hosts will get the IP from the local L3 cisco switch OR router. Kindly let me know how to proceed further if at all it is possible.


Thanks in advance!

Gaurav Sharma

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Loading.
Giuseppe Larosa Sun, 11/15/2009 - 00:04
User Badges:
  • Super Silver, 17500 points or more
  • Hall of Fame,

    Founding Member

Hello Gaurav,

I would look at providing a backup link to reach the datacenter.

This is certainly possible.


For setting up a dhcp server when the wan is down you should use an EEM embedded event manager that reacts to wan link failure by injecting ios command lines for the DHCP pools.


see ask the expert with Joe Clark


http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Network%20Infrastructure&topic=Network%20Management&topicID=.ee71a02&fromOutline=&CommCmd=MB%3Fcmd%3Ddisplay_location%26location%3D.2cd4b0c6


you may need to copy the whole url to the broswer to open the link


However, what would happen when the wan link is up again?


Another script should clear bindings and should remove the DHCP pool


so I think the more correct solution is to provide a backup link.

Also the problem affects only PCs that are switched on when the wan is failed all other PCs should use their current lease.


Hope to help

Giuseppe


Actions

This Discussion