Zepanda66:

 

Spent the afternoon trying to resolve this and it looks like the problem might be on the ISP's end if this reddit post is to be believed. Oh dear. Maybe time to look elsewhere. 

 

 

 

https://www.reddit.com/r/PS4/comments/5bs5n7/lag_ip_packet_fragmentation_message_help/da60egd/

 

You have taken a single post as gospel, may not even be the RSP.

i note in that same thread, it's pointed out this typically happens on double nat setups too; ofwhich you are running..

@sounddude might be able to have a sniff around and see if anyone else is having issues. I'd expect there to be alot more posts about this if it was a wider issue though.