I have configured the pptp server on ubuntu 12.04 and these are the logs that I got when I connect to it through vpn client (win xp).
Dec 6 19:35:00 ubuntu pppd[1145]: Using interface ppp0
Dec 6 19:35:00 ubuntu pppd[1145]: Connect: ppp0 <--> /dev/pts/0
Dec 6 19:35:00 ubuntu pptpd[1144]: GRE: Bad checksum from pppd.
Dec 6 19:35:02 ubuntu pptpd[1144]: CTRL: Ignored a SET LINK INFO packet with real ACCMs!
Dec 6 19:35:02 ubuntu pppd[1145]: peer from calling number 10.10.10.254 authorized
Dec 6 19:35:02 ubuntu pppd[1145]: MPPE 128-bit stateless compression enabled
Dec 6 19:35:02 ubuntu kernel: [ 98.375862] PPP MPPE Compression module registered
Dec 6 19:35:05 ubuntu pppd[1145]: found interface eth1 for proxy arp
Dec 6 19:35:05 ubuntu pppd[1145]: local IP address 172.16.10.1
Dec 6 19:35:05 ubuntu pppd[1145]: remote IP address 172.16.10.234

I want to ask that it is succesfull connection or not?
I have doubt on two things?can somebody explain it.
1)GRE: Bad checksum from pppd.
2)CTRL: Ignored a SET LINK INFO packet with real ACCMs!
thanks