Re: pptp vpn issue

[mark <mark@menem.mine.nu>]

Caveman wrote:
<SNIP>
> Feb 10 21:39:02 server pppd[2767]: sent [LCP ConfReq id=0x1 <asyncmap
> 0x0> <auth chap MS-v2> <magic 0x6d8fe389> <pcomp> <accomp>]
> Feb 10 21:39:02 server pptpd[2766]: GRE: Bad checksum from pppd.
> Feb 10 21:39:02 server pptpd[2766]: GRE: xmit failed from decaps_hdlc:
> Operation not permitted
> Feb 10 21:39:02 server pptpd[2766]: CTRL: PTY read or GRE write failed
> (pty,gre)=(4,5)
<SNIP>

> GRE: Bad checksum from pppd. seems to be where things go bad.

Nope, that response is normal when you try to connect to it with a 
windows machine. Windows has a buggy way of connecting to a PPTP 
server. What else is new?

> I googled around and found you need to allow protocol 47 or gre
> through the firewall, which I did. However I still have the same
> issue.
> I have also tried dropping the firewall totally (iptables -F) however
> its still failing with the same error.
>
> I am totally lost for ideas, so any help would be great.
>
> Cheers,
>
> Caveman

It actually is "..GRE: xmit failed from decaps.." that is causing 
you troubles.

I managed to save this from googles cache:
http://64.233.183.104/search?q=cache:EOuw60wda_YJ:news.gw.com/comp.unix.bsd.openbsd.misc/%253C3ffc3683%240%24330%24e4fe514c%40news.xs4all.nl%253E+GRE:+xmit+failed+from+decaps_hdlc:&hl=nl

The interesting part is: "You might want to disable 'keep state' on 
the pptp connection."

Hope it helps,

Mark