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August 23, 2005

Port Blocking in London Hotel Continues...

Both Martin Geddes and Andy Abramson appreciate what it means to be the victim of Port Blocking.

I'm just especially irritated that someone at the hotel ISP choose to specifically block UDP traffic on port 5060. While I was in London I had hoped to spend some of my downtime beta testing a new build of pulver.Communicator but that will now have to wait until I return home.

On the positive side, except for the blocking of SIP traffic, I've been otherwise quite pleased with the quality of service provided by the connectivity in my room. Last night even though I was in London, I was able to get in my nightly shot of "Law and Order" on TNT and continue to be impressed with the quality of the picture on my SlingPlayer with sustained streaming rates ranging between 350-400k bps.

Oh, and I have been able to log into Party Poker without any trouble....but I now have to wonder if connectivity to sites like Party Poker would have been blocked if there was a casino in this hotel.

Posted by jeff on August 23, 2005 02:42 AM | Permalink

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Comments

Does a VPN introduce too much latency? There are now several rent-a-VPN services for those without corporate IT: Witopia.net SecureMyWiFi, HotSpotVPN.com, publicVPN.com, JiWire SpotLock, etc. They're about $5 to $15 per month depending on features (and use a range of standards: IPsec, PPTP, SSL). The SSL VPNs use the HTTP port, if I recall correctly, and unless the latency is too high, you'd get the double benefit of bypassing local port blocks and the security of not broadcasting your unecrypted POP passwords and other data.

Posted by: Glenn Fleishman at August 23, 2005 09:44 AM

Thinking more about it now. You could also build a "known sequence of port numbers" into pulver.Communicator as well. For example, let's say you set up proxies on port 5060, 5070, 6080, just for grins. You could build code into p.C that will try the call on 5060, if that fails try it on 5070, etc. This would then completely hide the fact that you're not using 5060 to the end user. A bit more Skype-like...

Posted by: Frank Miller at August 23, 2005 09:22 AM

There's a simple solution for FWD. Just start several instances of your proxies on different port numbers. Perhaps spread the proxies around in the UDP port space and advertise the port numbers on the FWD web site and/or user documentation. While 5060 is a "well-known" port, any decent SIP implementation should be able to get to FWD using any UDP port number and I really doubt that these people will be able to defeat multiple servers on multiple random port numbers...

Posted by: Frank Miller at August 23, 2005 09:19 AM

Great post, Jeff

Posted by: John at August 23, 2005 04:43 AM