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How can I tell if my network has a SIP ALG?

What is a SIP ALG?

A SIP ALG (SIP Application Level Gateway) is additional software built into some routers that attempts to help Voice Over IP traverse your NAT. In practice, most SIP ALGs cause intermittent problems due to reliability issues, and SIP ALGs are never useful or necessary to use Virtual Office.

Virtual Office does not require a SIP ALG in any way, and SIP ALGs should always be disabled on your network when using the Virtual Office Service.

How do I know if I have a SIP ALG?

Our "Remote Monitor" software has a built in SIP ALG detector.

As a Virtual Office customer we can assist in the installation of the Remote Monitor software to both guage your network performance and to detect SIP ALGs.

We also have an online SIP ALG Detector Applet. Applets are written in Java and require your browser to have Java installed and enabled to work. If your browser supports Java the applet below will perform the same tests. If not, as a Virtual Office customer we will assist you in the installation of a Remote Monitor to both automatically detect SIP ALGs so they can be disabled, and to guage network performance to insure good levels of service.

Java is not currently installed or supported in this browser.


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