Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Port security and DHCP Problem on a Catalyst 3550


My problem is that on a specific type of workstation which send only one "DHCP DISCOVER" during boot, the request is not fowarded on the network. When using another type of workstation wich send several "DHCP DISCOVER", the first one isn't fowarded but the DHCP is working because of the second request. When disabling the port security, the problem is not present. So my question is : is it normal that the first frame isn't fowarded on a secure port (it doesn't seem to be the case on 2924/2948/4003/4006)?

Thank you and excuse my imperfect english.


Re: Port security and DHCP Problem on a Catalyst 3550

I am not aware of any bug matching this criteria, but I have come across a bug where if the "ip helper address" is configured, then it wont forward the discover packet to other ports in the same vlan. Do you have this command configured? Check after removing it on the vlan interface. May be your problem is a duplicate of this problem too.