MTU issue in pfSense 2.0RC1



  • I don't know what is going on, but when I change the MTU of WAN1 and WAN2 to 1452, both of the DSL modems or at least their interfaces in the pfSense control panel go offline and I can no longer access the Internet until I reset the MTU to 1500 and reboot the pfSense box. I have a 2 port Intel 100Mbit NIC in the machine which the DSL modems are connected to and then 1Gbit NIC port on the Intel motherboard which is plugged into my switch. The DSL modems are handling PPPOE (not in bridged mode). This is a weird problem because I remember back in 1.2, I had the MTU set to 1452 with no issues.



  • You have to do that on the interfaces->assign->ppp page now not directly on the interfaces->WanX page.
    The later will change the ethernet interface mtu and not the pppoe established mtu.


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