On 2013/02/07 20:18, Christopher Zimmermann wrote: > On Thu, 7 Feb 2013 17:41:12 +0000 > Stuart Henderson <s...@spacehopper.org> wrote: > > > This is extremely useful as it permits carrying stacked vlans > > on Alix/net5501, and also permits carrying 1500 MTU packets within > > pppoe(4) using the RFC4638 support. > > So with 5.3 I can drop the max-mss 1452 on my alix router? Great!!! > Have much thanks for working this out! > > Christopher >
RFC4638/pppoe support works only in specific circumstances: your ISP and the whole path to it must be clean for MTU 1508 (1526 byte total frame size with the ethernet headers etc). In general this isn't going to work with standard ADSL modems however it is more common with VDSL modems (some of these e.g. huawei hg612 can also be used with ADSL) and GPON terminals. So... in some cases you will be able to reconfigure things so that you could get rid of mss clamping, but it's not going to be universal.
