This is a SIP ALG that actually works. It has been tested extensively with Asterisk, Vonage, and other SIP servers. It allows for VOIP applications to run on the router itself as well as behind the router. We have been shipping this SIP ALG for some time now. We tested the SIP ALG distributed with kernel 2.6.20.4 and it didn't work (none of the SIP ALGs distributed with the kernel that we've tested have ever worked). Signed-off-by: Carlos Munoz