ComputingConfidence

Do I need to check my max MTU size?

Likely so if you encounter problems with FTP uploads.

The max MTU size is limited by the largest allowed size along the line from client to server. On the Internet, it is mostly impossible to determine where the bottleneck might be. You most likely find the bottleneck at you own local router, DSL modem or your ISP. You can experiment with the command lines in the box below to see at what size your start getting fragmented packets.

Win-X: ping -f -l 1472 www.dslreports.com
Linux: ping -s 1472 www.dslreports.com
OS-X : ping -D -s 1472 www.dslreports.com

When you find the highest possible value of this MSS, then add 28 to this number and you have the MTU size.  So if the above suggested 1472 is just fine, then MTU is 1500.

You could investigate further to find out why your optimal MTU is not 1500 - but why bother?  Something in the chain is causing the fragment (maybe your NIC, maybe your router, maybe something at your ISP), and as long as you don't have to set the MTU too low (say below 1400), then it's probably not worth searching for the bottleneck.