Firewall causes excessive jitter

[Mensra]

I am running Merlin 384.9 on a RT-AC3100. When I enable the firewall, my jitter becomes bad. I mean like, toilet bad. More then 135ms bad. When it is not enabled, perfect. Help! Don't want to run without the firewall, but my VOIP is unusable with that kind of jitter. I have tried turning off other CPU intensive functions, (QoS, Traffic analyzer, Media server, VPN and AIProtection) no joy, it IS the firewall.

 

[L&LD]

When was the last time you did a full reset to factory defaults followed by a minimal and manual (no saved config file) configuration to secure the router and connect to your ISP?

 

[Mensra]

Long time ago. I have many saved port forwards and MAC rules for wireless. Not a trivial exercise.

 

[L&LD]

Long time ago. I have many saved port forwards and MAC rules for wireless. Not a trivial exercise.

I believe this is your issue right here.

You may be lucky and stumble on a sequence of steps that solve your issue, or, you can do a reset to factory defaults and follow that with a minimal and manual configuration to secure the router and connect to your ISP. I would also suggest formatting the jffs and rebooting the router 3 times with 5 to 10 minutes between boots. Finally, using the WPS button to erase the NVRAM is also a step that will ensure your router is in a good/known state.

After this, add features and change defaults slowly, testing your network extensively at each step. Don't forget to reboot the router and wait at least 10 minutes after it is up before changing anything else again.

The links in my signature below may be useful, let us know how it turns out. Be sure to take screenshots of all your router settings before you continue. It is also a timesaver to create a text-based file of these settings too. Search the forums here for the command that can save all your settings to a text file directly.

The reason I'm suggesting the above, while it seems drastic, is because I have not seen symptoms like yours before; this is what usually indicates that a full reset to factory defaults is what is required before going on a wild goose chase for random glitches or bugs like you're seeing now.