problems connecting to VPN server on Raspberry Pi (Debian) [closed]

Question

I have installed pptpd on my Raspberry Pi box (it's Debian-based for those who don't know), it's running but not working properly - I can't connect.

here's interesting log - me trying to connect:

pi@raspberrypi ~ $ cat /var/log/syslog | grep pptpd | tail
Aug 21 11:32:24 raspberrypi pptpd[1770]: CTRL: Reaping child PPP[1771]
Aug 21 11:32:24 raspberrypi pptpd[1770]: CTRL: Client 77.253.47.194 control connection finished
Aug 21 12:17:21 raspberrypi pptpd[1855]: MGR: PPP binary /usr/sbin/pppd not executable
Aug 21 12:17:27 raspberrypi pptpd[1856]: CTRL: Client 77.253.47.194 control connection started
Aug 21 12:17:27 raspberrypi pptpd[1856]: CTRL: Starting call (launching pppd, opening GRE)
Aug 21 12:17:28 raspberrypi pptpd[1856]: CTRL: EOF or bad error reading ctrl packet length.
Aug 21 12:17:28 raspberrypi pptpd[1856]: CTRL: couldn't read packet header (exit)
Aug 21 12:17:28 raspberrypi pptpd[1856]: CTRL: CTRL read failed
Aug 21 12:17:28 raspberrypi pptpd[1856]: CTRL: Reaping child PPP[1857]
Aug 21 12:17:28 raspberrypi pptpd[1856]: CTRL: Client 77.253.47.194 control connection finished

and

pi@raspberrypi ~ $ cat /var/log/syslog | grep ppp | tail  -n 25
Aug 21 11:32:24 raspberrypi pppd[1771]: but I couldn't find any suitable secret (password) for it to use to do so.
Aug 21 11:32:24 raspberrypi pptpd[1770]: GRE: read(fd=6,buffer=15b84,len=8196) from PTY failed: status = -1 error = Input/output error, usually caused by unexpected termination of pppd, check option syntax and pppd logs
Aug 21 12:17:21 raspberrypi pptpd[1855]: MGR: PPP binary /usr/sbin/pppd not executable
Aug 21 12:17:27 raspberrypi pptpd[1856]: CTRL: Starting call (launching pppd, opening GRE)
Aug 21 12:17:27 raspberrypi pppd[1857]: pppd 2.4.5 started by root, uid 0
Aug 21 12:17:27 raspberrypi pppd[1857]: Using interface ppp0
Aug 21 12:17:27 raspberrypi pppd[1857]: Connect: ppp0 <--> /dev/pts/1
Aug 21 12:17:27 raspberrypi pppd[1857]: peer from calling number 77.253.47.194 authorized
Aug 21 12:17:27 raspberrypi pppd[1857]: kernel does not support PPP filtering
Aug 21 12:17:28 raspberrypi ifplugd(ppp0)[1882]: ifplugd 0.28 initializing.
Aug 21 12:17:28 raspberrypi ifplugd(ppp0)[1882]: Using interface ppp0/00:00:00:00:00:00
Aug 21 12:17:28 raspberrypi ifplugd(ppp0)[1882]: Using detection mode: IFF_RUNNING
Aug 21 12:17:28 raspberrypi ifplugd(ppp0)[1882]: Initialization complete, link beat detected.
Aug 21 12:17:28 raspberrypi pppd[1857]: MPPE 128-bit stateless compression enabled
Aug 21 12:17:28 raspberrypi ifplugd(ppp0)[1882]: Executing '/etc/ifplugd/ifplugd.action ppp0 up'.
Aug 21 12:17:28 raspberrypi ifplugd(ppp0)[1882]: client: Ignoring unknown interface ppp0=ppp0.
Aug 21 12:17:28 raspberrypi ifplugd(ppp0)[1882]: Program executed successfully.
Aug 21 12:17:28 raspberrypi pppd[1857]: LCP terminated by peer (MPPE disabled)
Aug 21 12:17:28 raspberrypi pppd[1857]: Modem hangup
Aug 21 12:17:28 raspberrypi pppd[1857]: Connection terminated.
Aug 21 12:17:28 raspberrypi pppd[1857]: Connect time 0.1 minutes.
Aug 21 12:17:28 raspberrypi pppd[1857]: Sent 3630 bytes, received 6720 bytes.
Aug 21 12:17:28 raspberrypi pppd[1857]: Exit.
Aug 21 12:17:28 raspberrypi ifplugd(ppp0)[1882]: Link beat lost.
Aug 21 12:17:29 raspberrypi ifplugd(ppp0)[1882]: Exiting.

Can anybody see any clue in these logs? I don't know much about ppp nor pptp.

Answer 1

I myself encountered the error as well while trying to connect via PPTP VPN to my Raspberry Pi. After some searching on the error "kernel does not support PPP filtering", this seems to be an option that needs to be compiled into the kernel. (See last posts.)

To fix it you would either need to use a different kernel (or different distro+kernel) with the option compiled in to the kernel. You could also try to compile your kernel yourself, with the option enabled (advanced).