Changing MTU on the gui does nothing



  • Hello,

    I tried this on pfSense 2.4.4-RELEASE-p2, did a fresh install too to make sure it isn't a config issue, but there is something strange showing up on my install

    On the interfaces / WAN, there are two fields: MTU and MSS

    I tested the changes using this site: www.speedguide.net/analyzer.php

    I changed MTU to 1440, visit speedguide and nothing happens

    BUT if I change MSS to 1440, on speedguide the MTU field shows correctly, and MSS as 1400

    Is this a bug or I am understanding it all wrong?

    Thanks, have a nice day.


  • LAYER 8 Global Moderator

    @fernandodx-0 said in Changing MTU on the gui does nothing:

    understanding it all wrong

    Ding Ding Ding - you win yourself a cookie ;)

    Google mtu vs mss



  • Please enlighten me in one detail

    If I leave MTU on default, and on my Desktop Ubuntu I change my NIC mtu to 1440, speedguide shows the value I entered

    I revert my Desktop NIC to 1500, and change pfsense MTU on the WAN interface to 1440, no changes are seem on speedguide

    But if i change the MSS value of the WAN interface on pfSense, them the MTU value changes to 1440 on speedguide

    399f5df7-1524-4ea9-a235-54f8ab802482-image.png

    feedec90-cbf4-4921-82d3-e8122cba164e-image.png

    Why changing the MTU field on the gui din't show on speedguide, but MSS did actually reflect the value I entered for MTU?

    Thanks!


  • LAYER 8 Global Moderator

    Because they are completely different things.. Again google mtu vs mss..


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