Having problems with your SIP telephone from home?

I decided to bring one of the new Aastra 9480i IP telephones home and it would not work.  At first I blamed Time Warner Cable, afterall, I have had more problems with my cable broadband in the past year than I ever had with dialup and the first time I attempted to bypass my router I was unable to get my telephone to work.

Long story short, if you have a router at home and you can not get your SIP device working check to see if your router has “SIP ALG” enabled.  If it does, chances are that is the problem- it seems that many routers actually break SIP with this “helpful” feature.   After disabling SIP ALG I was able to place and receive calls without any problems.


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