OpenVPN Support Forum

Dear all,

For my company, I am involved in maintaining an OpenVPN server that is used with
OpenVPN clients for Linux, Windows, Android and iOS. Recently we have had some trouble
with a router (at an ISP that we have no control of) that is not letting through the packets
with the default MTU size of 1500.

After reading earlier posts on this forum, I have learned that mssfix and fragment can be
used to make OpenVPN cut-up the packets before sending them into the UDP connection. Also
I have learned that this is not an option for the iOS and Android clients.

There is also a discouraged option of using the link-mtu and tun-mtu to influence the packet
size of the low level UDP packets and the MTU of the tunnel respectively. I would think
that tuning down the link-mtu to 1400 would do the trick.

My questions are:
* Could this solve my issues?
* Is the link-mtu supported by the iOS and Android clients? (I read tag #334, where the
last comment is that it still doesn't work)
* If not? Is there another solution I can use?
* If I tune down the link-mtu, would it be recommended do adjust the tun-mtu as well?

Regards,

Ronald

Ronald,

We are also facing the same issue?

Were you be able to resolve this issue?

Thanks.

It might be worth trying a TCP based VPN ....