Skype is opening an abnormal amount of sessions during operation. What I mean by this is that it is creating several hundred (read 900+) active connections while running in windows. This is a bit of a problem for me. When active sessions go above 4000 no new sessions can be made by any user until old sessions are used. This becomes a problem when one or 2 users take around 900 sessions each.
We were able to keep the entire network from going down by simply limiting the number of active sessions per user to around 256. This allowed us to circumvent the entire network getting dragged down, but the users that were using the massive amount of sessions still get hosed.
The only way to fix it at this point has been to disable skype auto connect, and then reboot the machine and keep the user from using skype. Any help with this would be greatly appreciated. I am pretty sure this only started happening with the latest version of skype 5.5
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Accepted Solutionby ruffyen
Ok I finally think that I found the issue. My problem seems to be surrounded by the amount of contacts that I had. We use skype internally as an IM system and as an IT guy I have pretty much everyone in the company on my skype account. I was up around 80ish contacts when experiencing the issue.
I noticed that some of the connections that skype was making seemed to be connecting to local IP addresses on the network. I assume it does this to identify user available status etc. So I decided that to trim those connections I should remove all users I havent chatted with in the last month or so.
I got my 80 contacts down to around 35 and the problem seems to be resolved. With 80 contacts I was regularly seeing 160 Skype connections, after the pruning skype connections dropped to around 10 connections and NONE of them are LAN addresses. At this point I have told people in my organization to prune contacts as well.
Does anyone on this forum know if there is a limit to the number of contacts a user is allowed to have. I am assuming that 50 is a decent round number between the 80 i had and the 35 i have now. I am going to continue to monitor this problem on my network but for now I am going to mark this as the solution until someone tells me otherwise.
I'm curious, by what measure? Does Tcpview show this on a given machine? With it, I've never seen more than about a dozen connections. Do you have to be doing something in particular to see it spike?
I am on the router. It is an SSG5 Juniper. I have various scripts that parse the get session output and can tell me the amount of sessions opened on a various IP. In this case my IP was the culprit and when looking at the port associated with all the connections I used netstat -nao on my local machine to identify the associated PID, then used tasklist to get the exe associated with the PID and all 200+ connections are for skype. Please note that it is 200 connections right now because we limited the amount of connections an IP address can have to 256.
I shutdown skype and around 3ish mins later the internet is back on and connections have dropped to around 50ish.
I am running it now and will run it on any affected systems. And I will let you know. This oddly is not something that can be duplicated easily...
bit.ly / ofDjvc -- Output of just the skype sessions connected. (add http:// and remove spaces)
10.203.9.123/39428 (myIP/Skype_Port_Used) as you can see 222 connections
TCPView only shows around 20ish connections. So one of two things is happening here. Either skype is opening connections and then not properly closing those connections or tcpview isnt seeing all the connections. Any ideas? At this point I am going to go to an older version of skype.
Unknown to me, it turns out that TCPView, along with a competing program called CurrPorts, are weak on UDP, at least with P2P programs. This happened to come up in another thread here. See the sample output of another program, SmartSniff, here:
Once you narrow things down by filtering on your Skype port, you should see a lot more than with TCPView, but it doesn't break it out (that I can see) like your example, which has repeated lines for some of the same external IP addresses. For comparison, I've had SmartSniff going for about 10 minutes here with Skype, and it shows 56.
Does your router have a UDP timeout setting? The one in DD-WRT is on a pretty tight leash: 120 seconds.
I will have to check with my Firewall provider to see what the UDP session timeout is, but I do know for a fact that even after I killed skype on my local machine I could actively see UPD connections to the port Skype was using at the router open for over 30 mins.
30-08-2011 22:01 - edited 30-08-2011 22:03
I see that the ScreenOS Cookbook says that "Generic UDP Service" has a timeout of 1 minute, so what you were told would seem to be the case, though I'm not sure what version it's referring to. But maybe this comes down to some quirk of ScreenOS, something else that needs to be tweaked there. I don't know if you're the one who does the router updates, but it looks like it's up to v6.3.0r8.
Did you ever confirm that it doesn't happen with Skype 5.3? (BTW, does unchecking uPnP in Skype Options buy you anything?)