I have an HP ProCurve 2910al (J9146A) and I am being requested to drop connections or timeout connections with half-open TCP connections. I am having trouble finding commands or even understanding what half-open TCP connections are. My ports on the switch are set with port-security to specific MAC addresses. What commands can I use on my switch to drop or timeout half-open TCP connections?
Half-open TCP connections are connections that have not completed the three-way handshake (yet). For inbound connections, a SYN packet has been reveceived without an answer to the SYN/ACK reply.
As a layer-3 switch, the 2910al is a stateless router. Therefore it has no knowledge about half-open or completed connections that is has routed (or even switched).
If you want to defend the switch itself against DoS attacks you should move the management to a VLAN that normal users can't connect on. Additionally, you can use ACLs to deny unwanted packets as soon as they enter an edge/access port. Furthermore, you might want to disable the web interface if it's being attacked.
If you post the (sanitized) configuration and a better description of the actual problem we can provide more detailed help.