said by taytong888:Hello decx,
Which ATA are you using? I am using Linksys SPA-3102.
My main router Netgear does not have any SIP ALG feature, I did look very carefully. It seems Netgear removed SIP ALG from Model WNR-834B V2 in one of the firmware upgrade.
I'm not using a Cisco SPA but a few OBi, but they still have many of the same configuration options.