How can I force a DHCP client to renew its IP address??

[David Babiano Rodriguez]

Hi to all,

I have installed in a customer, a Cisco 2801 who has configured a DHCP pool. This router takes a reload every month (by maintenance purposes), when it is up (in the network we have AVAYA phones working fine, it's a call center), this phones takes a reload to renew the ip, which is assigned by the DHCP pool.

The problem is when some phones try to renew its IP address (after the router reload), the phone detects a IP conflict an it forces a reload. This reload normally is in production hours, the agents lose their phones and they can't work......

There is some option to force the DHCP client to do a IP renewal from the DHCP server???

Thanks to all.

Regards.

David.

[Karsten Iwen · Accepted solution]

First of all you should investigate what is going so horribly wrong in your network that you have to reload your router every month (and even worse in production hour). If it's an instability, have you tried to update to a newer IOS-version?

Regarding your DHCP-problem. For that you just have to configure your DHCP-server correctly by specifying a database-agent:

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/12-4t/dhcp-12-4t-book/config-dhcp-server.html#GUID-5F022CF5-671E-49E7-8FBD-69997EEBC730 

With this function the router stores all bindings and knows (also after a reload) which addresses are already assigned to which system.

[David Babiano Rodriguez]

Thanks to reply me....

The reload is scheduled when the call center is out of business hours (of course), but the problems with the dhcp are inside..... The router doesn't erase buffers and it hangs every two months approximately (possibly the IOS c2801-adventerprisek9-mz.124-22.YB8 has some problem but I don't discard some hardware problem, is a refurbished router....)  

I'm going to test it.

Thanks!!

Regards.

David

[Karsten Iwen]

I would try a 12.4(24)T8 image. I remember that this release was quite stable, But I don't use 12.4... any more for long.

In addition to that, do you really need an AdvEnterprise image? If not, then use the one with the least features. A feature that is not available in an image can't cause problems.

[Martin Carr]

Exactly this, you are working around problems, instead of trying to resolve the underlying issues!

Martin