I have enabled port 1 as a trusted (DCHP server) port and ports 2 - 24 as untrusted (client) and no matter where i put the DHCP server (Draytek Router) my client gets an IP address. Should the port that i connect the DHCP server to (ie port 22) not be shut down when it responds from a DHCP request from client PC in port 7?
When a switch receives a packet on an untrusted interface and the interface belongs to a VLAN in which DHCP snooping is enabled, the switch compares the source MAC address and the DHCP client hardware address. If the addresses match (the default), the switch forwards the packet. If the addresses do not match, the switch drops the packet. "
The switch has the MAC address and DHCP Client hardware address from your DHCP server when you had it on a trusted port so it forwards the packet even when placed on untrusted ports after the fact. You need to clear the DHCP Snooping database and try again.
After doing the command clear ip dhcp snooping binding this worked, thanks. Not sure about the database command as this does not seem to do anything or even when I do a show IP dhcp snooping database does it show anything.
I was expecting the port to shut down or see some kind of log when carrying out a show command but nothing!
It just stopped it giving out dhcp, is this how it should function?
I have same problem so I have tried fix that above guide but problem not fixed. I have created interface vlan 4009 on my remote switch and configured ip address dhcp on this vlan. DHCP addressing working when I remove ip dhcp snooping vlan 4009 however it's not working when add this command.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...