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Article #2Re: Need help regarding MTU, MCC, ICMP Headers ... !!!
From: Richard B. Gilbert
Date: Mon, 27 Oct 2008 13:07
Date: Mon, 27 Oct 2008 13:07
45 lines
3267 bytes
3267 bytes
pg wrote: > 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 http://help.expedient.com/broadband/mtu_ping_test.shtml > ( scrolling down to #5 where it ) says "Add 28 to that number (IP/ICMP > headers) to get the optimal MTU setting" > > On this page, http://www.speedguide.net/read_articles.php?id=157 > 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? AFAIK there is no benefit and great risk in changing the default!
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