06-26-2012 10:34 AM
I am looking for some help with DHCP Relay on a SGE2000 switch.
I have configured two VLANs on the switch, VLAN2 (192.168.10.x/24) and VLAN3 (192.168.9.x/24). I have the switch in Layer 3 mode. I have configured the DHCP relay server of 192.168.10.4 and the DHCP Interfaces as VLAN3. All of the IP Static Routes were generated by the switch.
If I put a client computer on a port that is Untagged VLAN 3 and try to get a DHCP address from the server on an Untagged VLAN 2 port I never get a response back.
I have done some packet captures and here is what I have found:
I can't seem to get a DHCP address to any system not on the same VLAN as the DHCP server. Option 82 is disable and I did try enabling it, which made no difference.
Any help would be great.
Thanks,
Phil
Solved! Go to Solution.
06-26-2012 09:41 PM
Hi phil,
Have you created a static route on the DHCP server that points back to the 192.168.9.0/24 network.
The gateway for that network, from the DHCP relay servers perspective, is the VLAN2 IP address of the SGE2000 switch.
i would think that if you tried to ping the VLAN3 switch IP address from the DHCP server now, you will not get a reply.
When you create a static or persistant route in the DHCP server, you then should be able to ping VLAN3 IP address of the switch.
regards Dave
06-26-2012 09:41 PM
Hi phil,
Have you created a static route on the DHCP server that points back to the 192.168.9.0/24 network.
The gateway for that network, from the DHCP relay servers perspective, is the VLAN2 IP address of the SGE2000 switch.
i would think that if you tried to ping the VLAN3 switch IP address from the DHCP server now, you will not get a reply.
When you create a static or persistant route in the DHCP server, you then should be able to ping VLAN3 IP address of the switch.
regards Dave
06-27-2012 06:41 AM
Dave,
Thanks for the response. After reading your post I tried to ping the switch on the 192.168.9.0/24 network and could not get there. Once I switched my default gateway on my DHCP server to the switch IP on the same VLAN everything worked. I can now get DHCP address on VLAN 3.
Thanks,
Phil
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