Switch/DNS Issue

A core switch has 5 directly connected switches attached by fiber, all have the same trunking configuration (except allowed VLANs differ), the same is mirrored on the core switch.

3 out of 5 switches are able to ping the name servers but pinging from the other two fails. I cross matched their scripts looking for discrepancies but could not find any. The VLAN configuration on the core switch are all identical except for their respective VLANs again.

End users connection to the two failed switches are getting a 169. IP. What could be the issue?

Can ping core switch from the failed switches, or anywhere else in the network. show interfaces show the trunk ports as up/up, on the core and on the distribution switches.

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Comments

Heero

169 addresses means that the computers aren't correctly getting an IP through DHCP. Figure out that issue first.

wgroom

It sounds like one of the necessary VLANs that your DHCP server is in is not allowed across the two trunks to the affected switches. Check your VLAN allowances.