ip helper-address

[amcsystemstech]

I don't usually have to make changes to our cisco routers, but we are moving a bootp server on our frame relay network and the company that usually provides support is unavailable. I think I know what needs to be done, but I want to make sure before we make the move.

First, to remove an ip helper-address setting, I would use the following commands:

enable

config t

interface <Ethernet Interface Name>

no ip helper-address <bootp server address>

exit

wr

Second, to add an ip helper-address setting, I would use the following commands:

enable

config t

interface <Ethernet Interface Name>

ip helper-address <bootp server address>

exit

wr

Is this correct?

Thanks,

Andrew M. Campbell

[thisisshanky · Accepted solution]

You got it right! Notice that when you remove the helper-addresss, new clients who come up on a remote lan will not receive IP addresses. Also if Netbios browsing is done across subnets, those packets will not go across because Helper-address, by default enables forwarding of 8 udp ports including Netbios.

[smif101]

Yes you are exactly correct, however after you type in the no ip helper-address command you can then enter in the new ip helper-address command instead of exiting back out of config mode. Ensure that you do a copy run start to save your config after your done.