[NTLUG:Discuss] Bandwidth problems with poptop

[Rob Apodaca]

On Wed, 2004-01-07 at 18:00, David Stanaway wrote:
> Is anyone using poptop for 'Doze VPN clients?
> 
> I am using it with MPPE encryption, but get low throughput which does
> not seem to be constrained by CPU at either end.
> 
> XP Client transfering at 20kb/s @ 5-10% CPU
> 3GHz Xeon linux poptop server. 0.2% CPU
> 
> I have tried changing the pptpd.conf spped setting (For the baud rate
> for the ppp connection) but this seems to have no effect.
> 
> Does anyone have any other suggestions?

The poptop documentation is pretty light on details. When I first
started using it, I wrestled with it for months before getting it
working correctly.

This is the option file that I found has worked best. These options are
if you patched ppp and kernel to use 128 bit encryption. I believe it
came from the shorewall website:

ipparam PoPToP
lock
mtu 1490
mru 1490
ms-wins xxx.xxx.xxx.xxx
ms-dns xxx.xxx.xxx.xxx
multilink
proxyarp
auth
+chap
+chapms
+chapms-v2
ipcp-accept-local
ipcp-accept-remote
lcp-echo-failure 30
lcp-echo-interval 5
deflate 0
mppe-128
mppe-stateless
require-mppe
require-mppe-stateless

Note the mtu parameter. If you are using dsl, this is very important.
If 1490 yields no joy, try lowering it.

If all of the client machines are running MS2000 or MSXP, you might want
to try openvpn.

Cheers,
-Rob