[pptp-server] Gave up waiting for 1 lost packets

[Justin Kreger]

try lowering your mtu and mru... down around 750 works nice.  Smaller
packets might help.

> name *
> lock
> mtu 1490
> mru 1490
> proxyarp
> auth
> #defaultroute
> +chap
> +chapms
> +chapms-v2
> ipcp-accept-local
> ipcp-accept-remote
> lcp-echo-failure 3
> lcp-echo-interval 5
> deflate 0
> mppe-128
> mppe-40
> mppe-stateless
> ms-wins 10.1.1.9