I spent hours troubleshooting my network and finally figured out that SIP ALG was breaking everything. If you’re experiencing weird connectivity issues with Safari, App Store, Stremio, or even gaming NAT problems, this might be the fix you need.

My setup was pretty standard: modem in Bridge Mode, Deco X60 handling PPPoE, UPnP disabled, MTU 1492. My MacBook had issues where Safari took forever to load Google or Apple’s website, and App Store wouldn’t download or update apps. On my LG TV, Stremio + Real Debrid was buffering even on small 3GB files, while on another setup, a 60GB movie streamed flawlessly. On my PS5, COD Black Ops 6 had Open NAT when using port forwarding, but occasional ping spikes when the router was in AP mode.

I tried everything—switching PPPoE vs. AP mode, adjusting MTU (1492, 1452, 1400), enabling/disabling UPnP, changing DNS… nothing worked.

Then, I randomly disabled SIP ALG, and BOOM—everything started working perfectly. Safari and App Store loaded instantly. Stremio was buttery smooth, even with large files. COD stayed Open NAT with no ping spikes.

Why was SIP ALG causing this? & What even is SIP ALG?