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Quick question about MaxMTUs

Zucarita9000

Golden Member
I have my NIC connected directly to my router, wich is using a MaxMTU of 1460 (this is the size I ended up with after a few ping tests to my server). Now, wich should be my NICs MaxMTU? 1500? 1492?? 1460??
 
how does pinging help you select a MTU size???? are you adjusting the size of the ping packet? does windows allow that?


and jesus f___ing christ man, how long did it take you to put together your link there for system specs??? (it looks very nice)
 
Originally posted by: Abzstrak
how does pinging help you select a MTU size???? are you adjusting the size of the ping packet? does windows allow that?


and jesus f___ing christ man, how long did it take you to put together your link there for system specs??? (it looks very nice)


Basically, you ping your ISP by doing a ">ping -f -l 1492 www.yourisp.com" This sends 1492 byte packets to your ISP server (the normal is a 32 byte packet). Now, the largest value that does not give you the error "Packet needs to be fragmented, but DF set" will be your ISP's MTU.
In my case, the largest value was 1460.

And yes, it took me a while to gather all the hardware pics. It's a pain in the a** to keep it updated, with all the Windows hot fixes coming out the last few days...

 
cool, didnt; know windows was capable of specifying the packet size of a ping...

I would think that the max mtu you set on one thing should be the max everywhere to prevent fragmentation. I highly doubt your going to "see" the difference, but I would make it 1460 or less...

and, man, I just wouldn't have the patience to keep up a page like that
 
Assuming your OS and router both are reasonably modern, just leave your NIC at 1500. Path MTU discovery will cause the right thing to get figured out automagically.

The advantage to leaving this alone is that if you talk to any other host on your LAN, it'll be at 1500. (the delta between 1500 and say 1460 is effectively unnoticeable, but suppose you have a device like a network printer that isn't smart enough to do anything but 1500, now you can have some issues)

Unless there's a problem you're trying to solve, leave it alone.
 
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