Your ISP supports RFC4638, which means you can have the full size MTU=1500 for the pppoe-out1 interface. You can then keep MTU=1500 for your bridges and other vlans.
First you should increase the MTU of ether1, and then of vlan6 to 1508. This is not strictly necessary to achieve MTU 1500 for pppoe-out1, but is needed if you want to have MSS (IPv4 TCP) at maximum (1460 bytes) when the setting "Change TCP MSS" is set to "Yes" in the corresponding PPP profile under PPP Profiles.
Then in the configuration of the pppoe-out1 interface. set both Max MTU and Max MRU to 1500:
Redial, and Actual MTU will now be shown as 1500. No more MTU adjustments are needed in your LAN or your IPv6 ND settings. You can go to https://www.speedguide.net/analyzer.php to verify that your MTU is now 1500 and MSS is 1460 for IPv4 TCP.
First you should increase the MTU of ether1, and then of vlan6 to 1508. This is not strictly necessary to achieve MTU 1500 for pppoe-out1, but is needed if you want to have MSS (IPv4 TCP) at maximum (1460 bytes) when the setting "Change TCP MSS" is set to "Yes" in the corresponding PPP profile under PPP Profiles.
Then in the configuration of the pppoe-out1 interface. set both Max MTU and Max MRU to 1500:
Redial, and Actual MTU will now be shown as 1500. No more MTU adjustments are needed in your LAN or your IPv6 ND settings. You can go to https://www.speedguide.net/analyzer.php to verify that your MTU is now 1500 and MSS is 1460 for IPv4 TCP.
Statistics: Posted by CGGXANNX — Wed Apr 03, 2024 4:47 pm