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May 13th, 2007 02:00
Bug in SNMP on 6224 v1.0.0.27
It looks like there's a bug in SNMP in the 6224 v1.0.0.27 firmware.
If you query SNMP on the switch using an IP that isn't the closest (routing-wise) to the source of the SNMP query, the switch responds using the source address of the closest IP to the SNMP client. Naturally since the reply traffic is from a different source IP address than the client queried, SNMP doesn't work.
Take this hypothetical network for example:
http://chrisbuechler.com/temp/6224bug.png
If I query SNMP on 10.0.10.254 from client 1, it works. If I query 10.0.30.254 from client 1, it replies with a source IP of 10.0.10.254.
If I query 10.0.10.254 from client 2, it replies with a source IP of 10.0.30.254, so it doesn't work. If I query 10.0.30.254 from client 2, it doesn't respond at all.
Why would it not respond at all when using some VLAN IP's? It seems many of the VLAN IP's don't respond, but the one IP that does reliably respond, the one with the default gateway of the switch, always responds.
Routing and everything works fine (this is setup for L3), and from client 2 I can use HTTPS and SSH to 10.0.10.254 with no problems. HTTPS and SSH only answer on the VLAN IP 10.0.10.254.
Two possible resolutions:
1) Can I make it stop replying with the wrong source IP? Upcoming firmware update maybe? This is definitely a bug, a network device should never respond to any traffic directed to it using a different IP as the source in the reply traffic.
2) Can I make the management protocols listen on all VLAN IP's? Then I can query the IP closest to the client, which will work around this bug.
Message Edited by cmbuechler on 05-12-2007 10:49 PM
If you query SNMP on the switch using an IP that isn't the closest (routing-wise) to the source of the SNMP query, the switch responds using the source address of the closest IP to the SNMP client. Naturally since the reply traffic is from a different source IP address than the client queried, SNMP doesn't work.
Take this hypothetical network for example:
http://chrisbuechler.com/temp/6224bug.png
If I query SNMP on 10.0.10.254 from client 1, it works. If I query 10.0.30.254 from client 1, it replies with a source IP of 10.0.10.254.
If I query 10.0.10.254 from client 2, it replies with a source IP of 10.0.30.254, so it doesn't work. If I query 10.0.30.254 from client 2, it doesn't respond at all.
Why would it not respond at all when using some VLAN IP's? It seems many of the VLAN IP's don't respond, but the one IP that does reliably respond, the one with the default gateway of the switch, always responds.
Routing and everything works fine (this is setup for L3), and from client 2 I can use HTTPS and SSH to 10.0.10.254 with no problems. HTTPS and SSH only answer on the VLAN IP 10.0.10.254.
Two possible resolutions:
1) Can I make it stop replying with the wrong source IP? Upcoming firmware update maybe? This is definitely a bug, a network device should never respond to any traffic directed to it using a different IP as the source in the reply traffic.
2) Can I make the management protocols listen on all VLAN IP's? Then I can query the IP closest to the client, which will work around this bug.
Message Edited by cmbuechler on 05-12-2007 10:49 PM
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bh1633
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May 14th, 2007 12:00