RT-AC86U 384.19 Unable to set DNS in WAN tab

[kavsak]

Just set up a new AC86U with 384.19. All seems to running fine except when I try to set a DNS manually in the WAN tab I get "Please enter a value between 576 to 9000". Entering a number tells me that it is not IP address.
Does anyone have any ideas?

 

[jcinwa]

I had that problem the other day as well, it was the WAN MTU in my case - default seems to be 1500 but if you tinker with some dns settings it seems to get blanked out and then it asks for a value.

 

[ColinTaylor]

@kavsak Sounds like @jcinwa has the solution, but after installing 384.19 did you factory reset the router and reformat the jffs as explained in the release notes?

 

[kavsak]

Thanks guys. Putting a figure in the WAN MTU sorted it. I didn't think that was necessary as it is in the optional(?) ISP special requirements section.