[RT-N66U] Changing MTU on L2TP

[BigDaddy0790]

Hey there guys.

I recently had a pretty weird issue with my router, which you can read about here if interested, but in the end, it looks like a incorrect MTU was to blame. I managed to change it on my PC and PS4, but iOS devices (all of which have the issue) are not allowing for such a change, so I'd really love to know of a way to change the setting on the router itself, just to end this week-long nightmare already. Any help would be appreciated!

I'm running Asuswrt-Merlin 378.52_2.

 

[wouterv]

Hey there guys.

I recently had a pretty weird issue with my router, which you can read about here if interested, but in the end, it looks like a incorrect MTU was to blame. I managed to change it on my PC and PS4, but iOS devices (all of which have the issue) are not allowing for such a change, so I'd really love to know of a way to change the setting on the router itself, just to end this week-long nightmare already. Any help would be appreciated!

I'm running Asuswrt-Merlin 378.52_2.

The MTU setting is availble in the Advanced Settings>WAN>Internet Connection page, but only if set to WAN Connection Type = PPPoE.
I guess you shall be able to change it as well through a Telnet session to the router with the ifconfig command.

 

[BigDaddy0790]

The MTU setting is availble in the Advanced Settings>WAN>Internet Connection page, but only if set to WAN Connection Type = PPPoE.
I guess you shall be able to change it as well through a Telnet session to the router with the ifconfig command.

Yes, something like a Telnet option is exactly what I was looking for. I have zero idea how to do that, however. Could you elaborate?

 

[BigDaddy0790]

Okay, I figured it out. Used Putty to connect to the router through SSH after enabling it in the system settings of the router, and changed MTU manually using ifconfig command, everything seems to work now. Although from what I understand such settings won't survive a reboot, but it's something at least.

 

[wouterv]

Good to hear.
Plase share the exact steps you made to change the MTU setting.

 

[BigDaddy0790]

Good to hear.
Plase share the exact steps you made to change the MTU setting.

I enabled SSH access on the router itself under Administration-System menu, then used software called Putty to connect to it in SSH through 192.168.1.1, checked current MTU using ifconfig command (it was 1500 on all adapters), and then changed it to 1460 using command "ifconfig eth0 mtu 1460" on eth0, eth1 and eth2 since changing it only eth0 didn't seem to help right away. After all that, iOS devices started loading the pages without problems mentioned in my original post.