Hello Carl,

you need to check all the network devices on the path:

Let's suppose you have this topology:

PC1--SW1-R1--wan--R2--SW2--PC2

the LAN switch port where PC1 is connected

the LAN switch port where R1 is connected

the LAN interface on router R1

the WAN interface on router R1

the WAN interface on router R2

the lan interface on router R2

the lan interface of SW2 where R2 is connected

the lan switch port where PC2 is connected

the command is sh interface type x/y look for possible input or output erros in any of the ports listed above.

You need to give each of commands every 5 minutes and then check the errors fields

if no errors increments are seen in any section the problem can be on one of the two PCs.

If you see errors incrementing in one section you can narrow your search.

the first to look at are the access ports and the wan link on both sides but only checking all sections you can say it is not a network problem (sometimes happens)

Hope to help

Giuseppe