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Tagged aggregate link eats DHCP, ping works..?

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Occasional Visitor

Tagged aggregate link eats DHCP, ping works..?

I've got two 1910 switches, A and B, connected via a 2-port fiber trunk.

Everything works fine except that the trunk seems to be eating DHCP packets.


On A's side, there is a DHCP server and all the workstations get their addresses correctly.

On B's side, none of the workstation get any reply from the DHCP server.

If I manually configure an IP address (or set up a rogue DHCP server) on one of the "B" workstations, I can ping the DHCP server and any of the  "A" workstations just fine -- which I guess means that ARP broadcasts go through correctly.


The trunk/aggregate link is a tagged member of VLAN 1 on both switches, and all the workstation ports are VLAN 1 untagged access ports.


I've disabled IGMP and DHCP snooping, and broadcast suppression is at ratio 100%. No DHCP relay is configured on either switch as everything is supposed to be in the same IP segment.


Occasional Visitor

Re: Tagged aggregate link eats DHCP, ping works..?

Ok... this seems to have mysteriously fixed itself.


No idea what did it, but now DHCP is working also, and both ends of the aggregated link (49-52) are still "VLAN 1-3 tagged PVID 1234 (dummy) link type trunk" while the workstation ports are "VLAN/PVID 1 untagged access" -- as they are supposed to be.