Baby jumbo frames for pppoe connections (MTU 1508)

bradsm87

I'm also patiently waiting for >1492 MTU RFC4638 compliant support as my ISP in Australia supports it.

eri--

Try this and let me know if it works.

Put mtu on the WAN configuration screen to 1500
go to console and do ifconfig $realiface mtu 1508
on console then run ps -ax | grep mpd5
copy the command shown there and rerun it again see if that works.

bradsm87

@ermal:

Try this and let me know if it works.

Put mtu on the WAN configuration screen to 1500

go to console and do ifconfig $realiface mtu 1508

on console then run ps -ax | grep mpd5
copy the command shown there and rerun it again see if that works.

I'm still waiting on my Intel i350-T4 NIC. My current Broadcom doesn't play nice with any MTU above 1500. Will do as soon as it arrives.

bradsm87

I set the Ethernet MTU to 1508 and the PPPoE MTU to 1500 with the Intel NIC and the internet worked but I couldn't sent a 1472 byte ping past the gateway so I suspect that the PPPoE session was running 1492 MTU.

eri--

You need to set your MRU to 1500 on mpd.conf manually for that to trigger.
You can do this on the interfaces->assign->ppp tab by editing your pppoe session.

mattbunce

I have tried all that has been mentioned here…

Interface > WAN > MTU = 1500
Interface > (assign) > PPPs > pppoe0 > Advanced > MRU = 1500
console: ifconfig hn0 mtu 1508
console: ps -ax | grep mpd5

The second console command returns:
/usr/local/sbin/mpd5 -b -k -d /var/etc -f mpd_wan.conf -p /var/run/pppoe_wan.pid -s ppp pppoeclient

So I then run this command from the console. The internet connection drops and if then re-established.

Running ifconfig shows the mtu has remained 1508 on hn0 but is 1492 on pppoe0 - so I guess that means this isn't working correctly.

Any other tips?

NOTE: My pppoe connection is on hn0 - A virtual interface within Hyper-V

eri--

You have to set both mru and mtu on this file mpd_wan.conf

mattbunce

I have just upgraded to the very latest release and new ifconfig is showing an MTU of 1500, but this MTU is not achievable.

I couldn't get the MTU 1508 on hn0 to stick through a reboot, so I added hn0 as a new interface (OPT6) through the "Assign Interfaces" page and set the MTU as 1508 on this newly created interface.

After setting…

WAN interface MTU=1500
pppoe0 MTU=1500
pppoe0 MRU=1500

my mpd_wan.conf looks like this:

startup:
# configure the console
set console close
# configure the web server
set web close

default:
pppoeclient:
create bundle static wan
set bundle enable ipv6cp
set iface name pppoe0
set iface route default
set iface disable on-demand
set iface idle 0
set iface enable tcpmssfix
set iface up-script /usr/local/sbin/ppp-linkup
set iface down-script /usr/local/sbin/ppp-linkdown
set ipcp ranges 0.0.0.0/0 0.0.0.0/0
#log -bund -ccp -chat -iface -ipcp -lcp -link

create link static wan_link0 pppoe
set link action bundle wan
set link disable multilink
set link keep-alive 10 60
set link max-redial 0
set link disable chap pap
set link accept chap pap eap
set link disable incoming
set link mtu 1500
set link mru 1500
set auth authname "bthomehub@btbroadband.com"
set auth password pass
set pppoe service ""
set pppoe iface hn0
open

I noticed that as the pppoe connection gets established ifconfig briefly shows an MTU of 1492, but then displays 1500 after a few seconds.

Unfortunately…
ping -D -s 1472 bbc.co.uk tries to send the packet, but it does not succeed (no "message too long" or "frag needed and DF set"
ping -D -s 1464 bbc.co.uk succeeds

Which suggests an MTU of only 1492 is still possible.

If I run route get 8.8.8.8

route to: google-public-dns-a.google.com
destination: default
mask: default
gateway: [ISP GW]
fib: 0
interface: pppoe0
flags: <up,gateway,done,static>recvpipe sendpipe ssthresh rtt,msec mtu weight expire
0 0 0 0 1492 1 0</up,gateway,done,static>

Which shows that despite the higher MTU being showing in ifconfig this is not being used when it comes to 'route'.

I think this may be an issue with pfSense in Hyper-V because I cannot set MTU 1508 on the LAN interface and use it (route continues to show 1500) - however when I do exactly the same when running from the Live CD the route mtu does get changed - For this reason, I've raised a new post to get to the bottom of handling jumbo frames within Hyper-V before I do any more testing with PPPOE. You can see this thread here: https://forum.pfsense.org/index.php?topic=84730.0

eri--

I checked this.
Seems mpd5 did not yet get support for claiming this MRU during PADI sending on establishment.
I will give a quick look on supporting this and come back.

epek

Hello!

I just ran into quite the same troubles. I cannot set an mtu bigger than 1492 an my pppoe-wan.
Are there any news on the efforts in this matter?

Thank you
Epek