Port monitoring on ProCurve 4104gl

[Tom Egger]

Is it possible to get both inbound and outbound traffic on a port monitor on a 4104gl? According to the manual, it only monitors inbound, and it looks like that's all I'm getting, but I need to get both directions monitored.

[Matt Hobbs · Accepted solution]

There are a few crude ways you can do this. The easiest is if you know the path the traffic is going to take.

For example, if you wanted to monitor both directions of a server and its traffic was primarily going out the uplink port, then you would monitor the server port and the uplink port.

The other way which I haven't tested but have heard will work is to create a second VLAN specifically for monitoring.

In this situation you would create 3 ports in this VLAN, one is for the sniffer, one is for the server, and the other is to patch a link directly back into the original VLAN.

Since these switches have multiple mac-address forwarding tables this should work. The only downside is that you cannot enable spanning-tree at the same time as it would block the link between the 2 VLANs.

The best solution though is to use a different switch that supports both ingress and egress. It is only the 4100 and 8100 that do not support both ingress/egress mirroring.