Hello,
I'm trying to help out my university troubleshoot it's problem concerning OSX systems and Bluesocket wireless technology. We've been having several users come in on Mac systems that have been quarentined due to too many open network connections. Here's a quote on the Bluesocket policy:
"Each time a user makes a new network request, they create a new session that is being statefully monitored by the WG's firewall. If it is an existing connection (i.e. a download from a site), then it passes through the established connection. However, if they are scanning different machines, ports or have not been replied to by the destination host, a new session is set up.
Under normal circumstances, users have a relatively low number of firewall sessions (less than 10). You can see how many sessions your computer is using by typing netstat from the command prompt on a windows machine. In unusual circumstances, a user could be running a server with many clients trying to connect to it, or running a DoS attack, in which case, they will utilize a very high number of firewall sessions.
To limit a user to a finite number of firewall sessions, the administrator can enter a maximum number here. The default is set to
255. If a user attempts to copen more than 255 concurrent firewall sessions, the WG will disconnect other open sessions so that a single user cannot overuse network resources."Our Bluesocket is configured at the default value mentioned above. However, a netstat command from OSX's Network Utility reports that an average OSX machine connected (only wirelessly) has anywhere between
10,000-20,000 connections. Here's an example printout:tcp: 136087 packets sent 18908 data packets (1756503 bytes) 22 data packets (5062 bytes) retransmitted 0 resends initiated by MTU discovery 55730 ack-only packets (17833 delayed) 0 URG only packets 0 window probe packets 42896 window update packets 18536 control packets 220755 packets received 40665 acks (for 1763175 bytes) 8537 duplicate acks 0 acks for unsent data 174667 packets (188244806 bytes) received in-sequence 981 completely duplicate packets (1084878 bytes) 1 old duplicate packet 6 packets with some dup. data (2736 bytes duped) 12800 out-of-order packets (16285090 bytes) 300 packets (423700 bytes) of data after window 4 window probes 69 window update packets 18 packets received after close 0 discarded for bad checksums 0 discarded for bad header offset fields 0 discarded because packet too short 6624 connection requests 5315 connection accepts 7 bad connection attempts 0 listen queue overflows ! --> 11919 connections established (including accepts) 12267 connections closed (including 29 drops) 16 connections updated cached RTT on close 16 connections updated cached RTT variance on close 1 connection updated cached ssthresh on close 10 embryonic connections dropped 40660 segments updated rtt (of 40748 attempts) 154 retransmit timeouts 6 connections dropped by rexmit timeout 0 persist timeouts 0 connections dropped by persist timeout 3 keepalive timeouts 0 keepalive probes sent 1 connection dropped by keepalive 1613 correct ACK header predictions 152701 correct data packet header predictions
This number doesn't seem to be dependent on what programs/utilities are currently using network resources, as closing programs like iTunes and Safari don't affect any change (often, the number increases).
Now, by the Bluesocket policy, all OSX machines should be quarantined, right? Tens of thousands of connections are way more than the default maximum allowed (255) by the Bluesocket server, yet most OSX machines operate fine on the network. Those that come in quarantined on wireless don't have any abnormal programs or malfunctions that we can detect (they're running the same programs by and large; Mail, Safari, iTunes, etc.). We've contacted other universities that employ Bluesocket about this problem and none of them seem to share our experience.
Windows machines accessing wirelessly have connections within the acceptable range (255 or less).
My question is this: for any familiar with Bluesocket, is this a problem a question of configuration of the Bluesocket servers? Or is it a function of the Mac's behaving differently on the Bluesocket network, and special/additional configuration is required?
Also, is there any utility or program which I can use to monitor
*exactly* where these TCP connections are coming *from* and what they are for? I've tried IPNetMonitorX, but it only seems to alert me to the fact that these connections are open, and aren't much more descriptive than that.Any light you could shed on the issue would be very helpful! Thanks.