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Connection issue - ARP reply being blocked?


I have a computer connected to a Cisco SF300-24P switch (on an access port for VLAN 88).

I have a server connected to a TP-Link switch (on an access port for VLAN 88)

The Cisco switch is connected to a TP-Link switch with a trunk port allowing native VLAN 1 and tagged VLAN 88.

The computer cannot connect to the server, it cannot even ping it.

I did a tap on the trunk link between the switches and I see the computer doing an ARP request for the server and the server replies.  However when I tap the link between the computer and the Cisco switch, I only see the ARP requests go out.  The ARP reply is not getting through.  There is nothing in the config that should block this so I'm kind of puzzled. 

Any ideas? 


Diagram and config is attached.


PS:  If I replace the Cisco with another TP-Link everything works.

6 Replies 6

1. There is no sub interface. And the ARP request is making it out on the trunk as is the ARP reply from the server.
2. There is only 1 entry in the ARP table - the computer, as it’s the only device connected
3. There is only 1 device - there is no duplicate ARP entries
4. STP does not have a role here - it is a flat network with a single link between switches. Physically impossible to have a loop

please notice that some SW don't support UNTAG VLAN "NATIVE"
to check please not use any NATIVE VLAN in trunk between TP-Link SW and Cisco. 
I think that the Frame is tag with wrong VLAN.
check this point 

No difference.
Even with full tagging of VLAN 1 and 88 across the trunk, same thing happens.
On the trunk link between the switches I see the ARP request and reply but the ARP reply never makes it to the computer.
The ARP request is tagged VLAN 88 but the ARP reply is not. Is that right?

ARP request on the trunk (computer to server)


ARP reply on the trunk (server to computer)


echo is tag with VLAN 88 and the reply is untag !!!, as I mention before, the issue is with VLAN tag in trunk.

are you config the native VLAN in trunk ?? what is native VLAN of trunk ?

show interface g0/x switchport <-g0/x is trunk port 

check Native VLAN and allow VLAN.


please see the above link how you config the VLAN tag.

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