Is there a way to specify an "ip helper" rule for a specific address so that only UDP traffic from THAT ip address is forwarded to a different subnet?
For example udp from 192.168.1.15 -> 192.168.2.18
I know that you can do 192.168.1/24 -> 192.168.2.18, i was just hopping there was a way to only forward a single address.
Thanks!
Chris,
IP HELPER forwards DHCP REQUESTS. The workstation sends DHCP request when it HAS NO IP ADDRESS. It means that you cannot filter IP Helper requests based on IP addresses.
If you want to have a different DHCP servers for different PCs, you may install two or more DHCP servers (physical servers), configure certain MAC addresses to get a specific IP addresses (static DHCP assignment), and configure multiple "ip helper" addresses on your router. In this case your DHCP requests will be forwarded to ALL DHCP servers, but the only DHCP server with specific configuration (assignment) will reply to certain requests.
Good luck,
Mike CCNP, CCDP, CCSP, Cisco Voice, MCSE W2K, MCSE+I, Security+, etc. CCIE R&S (in progress), CCIE Voice (in progress)
------ Headset Adapters for Cisco IP Phones
Phoneswww.ciscoheadsetadapter.comwww.headsetadapter.com
Couldnt he use the IP helper address then just make an ACL to filter which packets are forwarded?
ip helper does a whole heck of a lot more than just dhcp. Helper by default forwards 8 different UDP protocols, you can also customize what it sends. To answer the OP's question, no, you cannot tell one device to go one way, another to go the other way via the helper command. If you know that there is one specific device that needs specific information either hard code it or create another vlan for it and send that vlan where you want it to go.
Have something to add? Share your thoughts — no account required.
Ask the community — no account required
