<![CDATA[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.

]]>https://forum.netgate.com/topic/143399/changing-mtu-on-the-gui-does-nothingRSS for NodeSat, 18 Apr 2026 20:30:30 GMTWed, 15 May 2019 19:35:18 GMT60<![CDATA[Reply to Changing MTU on the gui does nothing on Thu, 16 May 2019 15:11:02 GMT]]>Because they are completely different things.. Again google mtu vs mss..

]]>https://forum.netgate.com/post/843350https://forum.netgate.com/post/843350Thu, 16 May 2019 15:11:02 GMT<![CDATA[Reply to Changing MTU on the gui does nothing on Thu, 16 May 2019 14:56:34 GMT]]>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!

]]>https://forum.netgate.com/post/843348https://forum.netgate.com/post/843348Thu, 16 May 2019 14:56:34 GMT<![CDATA[Reply to Changing MTU on the gui does nothing on Wed, 15 May 2019 19:48:35 GMT]]>@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

]]>https://forum.netgate.com/post/843210https://forum.netgate.com/post/843210Wed, 15 May 2019 19:48:35 GMT