ip helper-address issue

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Apr 14th, 2009
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I have a centrally located Windows DHCP server that I want to lease addresses to a branch location. Currently, they are receiving addresses via an 1841. I have configured the new scope in DHCP and activated it. I configured the FA 0/0 on the 1841 in the branch location with the ip helper-address command pointing to the DHCP server and you guessed correctly, it's not working. I have disabled the DHCP server on the 1841 using no service dhcp, but I left the pool intact(not sure if this could cause a problem or not). I have a Sonicwall NSA 2400 firewall that is in the mix also so maybe it's causing a problem. I'm just looking for a way to methodically troubleshoot this. Thanks.

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thotsaphon Tue, 04/14/2009 - 08:40
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A service dhcp command is needed for an ip-helper command.

If you plan to use the DHCP server instead the router. Then delete the pool. Just to get rid of confusing things.

In case it still doesn't work. Let's check real-time log on the firewall. You need to allow UDP Ports 67 and 68. From NSA 2400 perspective you should allow those ports from outside zone to inside zone.




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