Hi there,
does anybody know if jumbo frames (i only need mini jumbo frames) are supported on the Netgear D7800?
Everything i tried to achive MTU 1508 for WAN doesn't work.
thanks
Hi there,
does anybody know if jumbo frames (i only need mini jumbo frames) are supported on the Netgear D7800?
Everything i tried to achive MTU 1508 for WAN doesn't work.
thanks
I think this might be related to a known stnmac driver bug which I understand is fixed in kernel 4.19+ (so should work with recent snapshot, but not 19.07.x or earlier) - see this thread for discussion. That thread mentions a possible workaround of forcing a large MTU (and how to implement it) which might help you if this is your problem.
Thanks for your link. I already tried it. I am on latest snapshot.
If i try to manually
ifconfig eth1 down; ifconfig eth1 mtu 4088; ifconfig eth1 up
or any other mtu, i get following error:
ifconfig: SIOCSIFMTU: Invalid argument
Hmm.. I don't think that thread is related at all now. I know that thread used ifconfig but the more modern command would be:
ip link set eth1 mtu 1508
I don't have my D7800 usable at the moment but I just tried this on an IPQ40xx device (GL-B1300, like R7800 & D7800 also has 2 CPU ports to switch so WAN is eth1) - with no interface down/up - and no errors were reported. The changed MTU was then reported when looking at the interface (ip address show) and I was then able to change it back without issue.
What else have you got tied to the WAN interface? (e.g. VLANs?). Also, do you actually have a live ethernet connection to the WAN (i.e. cable plugged into another network device such as a cable modem etc)?
yeah ifconfig or ip doesn‘t matter. the error is still the same.
Maybe you could try it on your d7800 sometimes.
There is a known issue, that the wan port on eth0 doesn‘t receive traffic if directly connected to a 100mbit modem.
So i am using vlans on eth1 to get a functional lan and wan.
Maybe this mtu problem is also related to the 100mbit problem.
As the d7800 is the my gateway router i only have limited time to experiment on this, so i tried the forum if someone can confirm that mtu 1508 on D7800 is working or not. Or maybe i have a configuration problem or maybe the vlans are not okey ... whatever
On a freshly flashed D7800 where eth0 is wan :-
root@OpenWrt:~# ifconfig eth0 mtu 1508
ifconfig: SIOCSIFMTU: Resource busy
root@OpenWrt:~# ifconfig eth0 down
**root@OpenWrt:~# ifconfig eth0 mtu 1508**
**ifconfig: SIOCSIFMTU: Invalid argument**
But on eth1 :-
root@OpenWrt:~# ifconfig eth1 mtu 1508
ifconfig: SIOCSIFMTU: Resource busy
root@OpenWrt:~# ifconfig eth1.1 mtu 1508
ifconfig: SIOCSIFMTU: Result not representable