Need help regarding MTU, MCC, ICMP Headers ... !!!

Oct 27, 2008 1 Replies
Need help regarding MTU, MCC, ICMP Headers ... !!! open original image

Hello !!



I'm trying to set the MTU value of a new PC -- dual boot, Linux & Windows -- and the lan card, the adsl modem, etc.



Since I'm not so bright, I went online to check. The more I check, however, the more I got confused.



On this page

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( scrolling down to #5 where it ) says "Add 28 to that number (IP/ICMP headers) to get the optimal MTU setting"



On this page,

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however, ( scrolling down to TCPWindowSize ) it is telling me that "MSS is generally MTU - 40 (20 byte TCP and 20 byte IP headers)" !



Which one is correct?



Just exactly how much do all the headers add on to a packet?


28 bytes or 40 bytes??

Let's say I've done the "MTU Ping Test" to various websites, and has obtained 1452 as _the_ optimum number. My question is this ---



What's the correct MTU setting?



Is it 1480 (1452 + 28) ? or Is it 1492 (1452 + 40) ?



In Windows, what numer should I set for the TCPWindowSize, the GlobalMaxTcpWindowSize, the TcpWindowSize and so on?



Is the MTU value the same for Linux, Solaris and Windows??



Please help !!



Thank you !


What problem are you trying to solve?

You don't normally need to play with the automatic setting of MTU unless you have some sort of problem, and you haven't described any problem.

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