We manage a company that has a Sonicwall 2400 with 3 HP switches. We have various nodes that get "disconnected" from the Internet. I believe out of 100 nodes, only about 7 are having these issues. When we look at the logs on the Sonicwall it says:
TCP handshake violation detected; TCP connection dropped - Handshake Timeout
Here are the steps we have taken so far:
1) Rebooted Firewall
2) Updated Firmware on Firewall
3) Rebooted Master Switch
4) Changed Default TCP Handshake Timeout from 30 seconds to 5 min
5) Change Default TCP Connection time from 5 Min to 30 min
6) Changed Syn flood from Always Proxy WAN to Watch and Report Possible Flood
Client could connect to httpS://www.google.com
and could ping google.com but web page for http://www.google.com
would load. She also had a solid VPN connection going.
Even after the above mentioned, still getting issues with "Handshake violation, TCP dropped".
Any ideas? I'm at my wits end....