IP Packet Fragmentation Not Supported

[SwiftCookie]

Yo DumaFam!

Just wondering if there's any remedies to a couple issues I've ran into after bridging my ISP modem router to the XR500 that weren't there before.

First issues is that I can now no longer access my ISP modem/router GUI. I actually managed to do it the other night but forgot how I did it lol, had something to do with changing a WAN IP or Gateway IP to my ISP Default Gateway IP on the XR500...******FIXED ISSUE ONE*******

Second issue is when I do a connection test on PS4 I get this pop up message now that says "The router in use might not support IP Packet Fragmentation, and some network features of the PS4 might be restricted." Usually that appears when I've adjusted the MTU too low but I haven't changed anything :/ ******FIXED ISSUE TWO, SORT OF***** I don't get the message if I lower the MTU in the XR500 from 1492 to 1491 and below., any ideas why that works? 

Also getting 100% Packet Loss now...******Image below still occurring. Unable to ping any servers, transmit failed etc******

Edited June 22, 2019 by SwiftCookie

[Netduma Alex]

Is there a reason you're not using 1500 for MTU? This is the default size.

[Guest Killhippie]

1 hour ago, Netduma Alex said:

Is there a reason you're not using 1500 for MTU? This is the default size.

PPPoE MTU is 1492, so IDNet my ISP use that. Not sure if the user is using PPPoE though.

[Netduma Fraser]

If I ping the URL you did then I get a response that uses a different IP address, yours is pinging a weird address that If I ping I also don't get a response, tried this on ISP hub also. Have you tried pinging something else normally?

I would recommend you properly check what MTU you use, changing the MTU without knowing exactly what you're doing will end up in fragmentation.