MTU: Difference between revisions

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Revision as of 20:54, 13 November 2017 (view source) AA-Andrew (talk \| contribs) m (→‎Explanation of the ping options:) ← Older edit		Revision as of 17:51, 19 November 2021 (view source) Reedy (talk \| contribs) (tt) Newer edit →
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For example: [[File:Firebrick-1500MTU-ping.png\|200px\|thumb\|a 1500 ping on FireBrick]] On Linux: ==Explanation of the ping options:== '''-c1 / / -n 1''' InThis ~~these~~is ~~examples~~optional, ~~we've~~it ~~only~~simply ~~used a count of one~~tells ping ~~using~~just ~~the~~to -csend ~~option~~a orsingle ~~-n on Windows.~~ping '''-M do / -f / -D''' ~~Means~~The important option! This means don't fragment the ping packet - we don't want the ping split into multiple packets when testing MTU! ''' -s 1472 / -l 1472''' The ~~option for~~ payload size ~~is -s, or -l on Windows~~. When setting size in ping, the size ~~printed~~ is the payload size - not the full packet size. '''The full packet size is''' <~~syntaxhighlight inline~~tt> payload (1472) + IP header (20) + ICMP header (8) </~~syntaxhighlight~~tt>, so this is 1500 in total! ==Two quick examples== This is despite the bridging modem used for the tests not claiming to support an MTU > 1500 octets and with PPPoE needing to send 1504 octets and receive 1508. ] [[Category:MTU]]