Here is an MTU test that can be used if you suspect packet fragmentation through your WAN connection or just want properly set your firewall wan MTU. First do the low test to establish a baseline. Then go from your current MTU setting down increments of “8”. MTU of 1500 is usually the default MTU but depending on the isp this can cause problems.
Ping -f –l “1404” www.yahoo.com
Low test: MTU 1404
Mid: MTU set to 1460
Any line using a vpn should not be below a 1450 MTU. It is a good idea not to set your mtu any lower than 1450 anyway unless required by your ISP.
Posted in: Server