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[disposition89]

Hello,

I have several entries similar to the one below in my router's log. My question is what is this SYN:ACK and should I be worried about it? Any help is greatly appreciated.

example:

Blocked incoming TCP packet from 95.173.165.142:80 to ???.??.???.??:1024 as SYN:ACK received but there is no active connection

[FurryNutz]

SYN and ACK stands for Synchronization and Acknowledgment. These are standard protocol for internet communication.

In your case the 4500 is reporting that someone from that IP address you listed is sending out these packets for unknown reason and since the 4500 logs are enabled, it's reporting to you what it's found and blocking.

The router is doing it's job.

[Trikein]

+1

Don't worry about it. You will see those in your logs sometimes. Specially if you play a lot of multi-player games. Anything less then 10-20 or a day (with heavy gaming) is fine.  If you see a couple hundred in a hour though..that could be something else. Your fine though.

As always, listen to the man with the FurryNutz.

[RiC0MD]

Just to add, in a normal TCP handshake, your PC would send a SYN request, which followed in reply with SYN ACK.  So the router is telling you somebody is trying to ACK to a connection you dont even have running, which is a way to possibly flood a connection.

[Trikein]

Nahh, its nothing that serious. I mean your right, it "could" be that, but I bet my hat they have a PS3. When ever you get a lag spike while playing a P2P multiplayer game, you get those in your logs. It has to do with how their(and most console games) handle their multiplayer. Plus if it was a DoS attack he would getting a ton more. Its a fair warning though.