Saturday, November 03, 2007

BSNL broadband blocks VoIP?

Yeah, yeah, it's been a while since I blogged. I won't bore you folks with miserable excuses. Let me jump right to the topic. I have this neat Grandstream Handytone 503 ATA (Analog Telephone Adapter) which allows me to connect a regular phone to it and make VoIP calls. I bought it from Telephony Depot, shipped to friend in the US and got it to India. Linksys PAP2 is more popular but this one is sleeker and has analog PSTN pass through which I liked (it doesn't work well with BSNL PSTN line, but that's a topic for another post). Any way, I have a VoIP account with Gizmo Project, voice quality is excellent, even better than Skype except for one small problem.

Suddenly, BSNL appears to blocking SIP ports. The clue is your device fails to register with the SIP server. For all I know this may be a regular thing because the problem keeps popping up for me once in a while in the short time I've used the device. I always thought it's a device issue but today I decided to dig deeper and here's what I found. Outgoing port 5060 (the SIP port) is definitely blocked for both tcp and udp (I test with an external BSD box where I have ssh access). So I found another VoIP provider called Callcentric which conveniently provides SIP port 5080 and SIP registration appears to go through fine.

The summary above looks simple but I had to go through a lot of trial and error. At first it appeared that ports 5061 through port 5080 were also blocked but right now just after I started posting this I was successfully able to get through to callcentric. I am using an excellent utility called sipsak to help me with debugging this. Any way, if BSNL is indeed blocking SIP calls that's really bad. VoIP is legal in India for individual users and BSNL has no right to do this. Ganesan


Anonymous said...
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Anonymous said...

IP Pbx

InteriorDeco said...

Interesting comments regarding SIP, My relatives have been using Grandstream Budgetone for 1+ year without issues. Any time we had issues, it was because of my insufficient knowledge of SIP(gizmoproject). Occasionally we have the problem of losing IP no and it takes 20 min for the reregistration to take place. Since my folks are low tech and I am in US, that is still an issue. but u can change it to 3 minutes to getter better registration responses.

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