ip forward-protocol nd default command versus DHCP via IP Helper not working

[Nicolas MATHEY]

Hi All,

We recently wanted to migrate external DHCP to a remote site: so basically just change IP helper address from one to another.

However migration failed as no device was able to get an IP from DHCP anymore and we had to roll back.

IP connectivity with the new offsite DHCP server is ok and there is no firewall in between, nor ACL, etc.

I was looking around ip forwarding command that my be used to block some broadcast specific traffic and realized that "ip forward-protocol nd" command was on devices between two sites.

My question is: does "ip forward-protocol nd" command means only allowing nd protocol? So in other words blocking all other UDP broadcast like BOOTP?

Thanks in advance,

Nick

[Milos Megis · Accepted solution]

Hi,
there are few protocols which are enabled by default
http://www.ciscopress.com/articles/article.asp?p=330807&seqNum=9

With this command you can only allow other protocols to be forwarded.

[Richard Burts · Accepted solution]

Nick

That command does not mean that it only allows the nd protocol. That command adds nd to the list of protocols that will be forwarded by the helper address. So BOOTP would still be forwarded. We do not have enough information to be able to identify the issue that prevented the remote DHCP but it would not have been the forward protocol nd.

HTH

Rick