DHCP Across Trunks

[Paul Smith]

Hi Guys,

I ran in to a situation during the week that I would like your opinion on. I set up and tested DHCP on a switch. I had a another switch connected through a trunk. I found that devices could ping and communicate across the trunk but DHCP could not?? I did a packet capture and saw the devices sending DHCP discover but not receiving a reply. When I set up DHCP physically on the switch where they were directly attached, all worked well and the devices could communicate right across the trunks. I would have thought DHCP would work across the trunks unless by design Cisco DHCP (on a switch) only works with directly connected devices?

[ITexpert]

Hello Richard,

Thanks alot for your help, I configure vlan 10, 20, 30 interfaces with ip addresses and Vlan 10 ,30 ports are getting dhcp ip addresses on both switches now but vlan 20 still getting APIPA.

Does vlan 20 is reserved for VOIP or something like that. 

Even on other Core switch vlan 20 is not providing IP addresses.

[ITexpert]

Hello Richard,

Its all working now.

Thanks

[Richard Burts]

I am glad that my suggestions pointed you in the right direction and that you have been able to solve the issue.I do really enjoy posts in these forums where someone posts with a problem and then  is able to work out the solution to their problem. Congratulations to you.

HTH

Rick

[ITexpert]

Thanks a lot Richard, I really feel blessed when somebody more experienced Tech pointed me in right direction.