I can ping a particular router say site X with 1500 byte packets pretty well from all of our wan sites however when I ping the same router from a pc or a lan device from the same wan sites the 1500 pings dont go through, 1472 pings go through but from 1473 onwards they fail. trying ping x.x.x.x -f -t -l 1473 gives me the following message : Packet needs to be fragmented but DF set.
Would it be an mtu issue within the retail carrier cloud or our router at site X? Some sort of mtu negotiation is failing maybe from a partcular device to our pc but which device? Plus why do router to router pings of 1500 bytes work and as mentioned above from pc to the same router it fails? If someone has come across this can you please advise.