pptpd

поднял сервер (centos 4.6) pptpd из локальной сети работает , а с
внешки не получается. (грешу на iptables но gre разрешены) в логах
вот что:

Aug 27 12:47:50 povolzie-nn pptpd[8474]: CTRL: Client ***.**.**.38 control connection started
Aug 27 12:47:50 strike pptpd[8474]: CTRL: Starting call (launching pppd, opening GRE)
Aug 27 12:47:50 strike pppd[8475]: pppd 2.4.3 started by root, uid 0
Aug 27 12:47:50 strike pppd[8475]: Using interface ppp1
Aug 27 12:47:50 strike pppd[8475]: Connect: ppp1 <--> /dev/pts/2
Aug 27 12:47:50 strike pptpd[8474]: GRE: read(fd=7,buffer=8056600,len=8260) from network failed: status = -1 error = Protocol not available
Aug 27 12:47:50 strike pptpd[8474]: CTRL: GRE read or PTY write failed (gre,pty)=(7,6)
Aug 27 12:47:50 strike pppd[8475]: Modem hangup
Aug 27 12:47:50 strike pppd[8475]: Connection terminated.
Aug 27 12:47:50 strike pppd[8475]: Exit.
Aug 27 12:47:50 strike pptpd[8474]: CTRL: Client ***.**.**.38 control connection finished