SSH/MTU Issues in OpenVPN tunnel on OpenWRT 21.02 RC3

[Etienne Champetier]

Hi Federico,

Le sam. 31 juil. 2021 à 20:33, Federico Capoano
<f.capoano at openwisp.io> a écrit :
>
> Hi everyone,
>
> I wrote about this issue in the forum and I was advised to post here
> as well so I'm following the advice.
> (Forum discussion:
> https://forum.openwrt.org/t/ssh-mtu-issues-on-openvpn-on-openwrt-21-02-rc3-linux-kernel-5-4-132/102686).
>
[...]
>
> OpenVPN version on clients with new firmare:
>
> OpenVPN 2.5.3 mipsel-openwrt-linux-gnu [SSL (mbed TLS)] [LZ4] [EPOLL]
> [MH/PKTINFO] [AEAD]
> library versions: mbed TLS 2.16.10
> Originally developed by James Yonan
> Copyright (C) 2002-2021 OpenVPN Inc <sales at openvpn.net>

openvpn-mbedtls is now build without lzo support, you can:
1) disable lzo on the server (actually the best thing to do IMO)
2) enable it in your build
3) use openvpn-openssl package

More discussion here: https://github.com/openwrt/packages/issues/15854

Best
Etienne

> OpenVPN version on clients with older firmware:
>
> OpenVPN 2.5.3 mipsel-openwrt-linux-gnu [SSL (mbed TLS)] [LZO] [LZ4]
> [EPOLL] [MH/PKTINFO] [AEAD]
> library versions: mbed TLS 2.16.10, LZO 2.10
> Originally developed by James Yonan
> Copyright (C) 2002-2021 OpenVPN Inc <sales at openvpn.net>
>
[...]
>
> Best regards
> Federico Capoano