# RFC4638 on PPPoE?



## Joost Mulders (Sep 7, 2017)

Hi, 

Does stock ppp (/usr/sbin/ppp) support RFC4638? (I.e, MTU > 1492 on PPPoE link).
If so, how to enable it?

I am running:

```
FreeBSD netx 12.0-CURRENT FreeBSD 12.0-CURRENT #0 r317181: Thu Apr 20 05:39:11 UTC 2017     root@releng3.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC  amd64
```

ppp.log contains:

```
Sep  7 12:19:53 netx ppp[394]: tun0: Warning: deflink: Reducing configured MRU from 1500 to 1492
```

Thanks much!
Joost


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## SirDice (Sep 7, 2017)

Topics about unsupported FreeBSD versions


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## Phishfry (Sep 7, 2017)

Have you tried /net/mpd5 ?

http://mpd.sourceforge.net/doc5/mpd20.html

https://forum.pfsense.org/index.php?topic=100219.0
You could track down these changes and see if they are now included in mpd5


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