So I've recently set up a PPTP server on my VPS, and it's working fine with numerous clients - however every time I connect I see an error in the logs, like below;
Oct 3 15:49:23 MACHINENAME pptpd: GRE: Bad checksum from pppd.
The connection is establish fine, and I can access the server with no issues once connected - so I'm not sure whether it's actually an issue or not. Can anyone shed some light on why it's happening, and how to stop it? I run OSSEC on this server (well, on all my servers) and so I'm getting this message emailed to me whenever I connect - and I'm loathe to add an ignore rule for it until I know it's not actually an issue!