[pptp-server] Error 778: Unable to verify the identity of the server

[Mark Burring]

A lot of my clients have been getting this error repeatedly: Error 778:
Unable to verify the identity of the server

Eventually it works. Just by staring at the logs it looks like a GRE
problem

Options:
lock
debug
proxyarp
+chap
+chapms
+chapms-v2     
mppe-40     
mppe-128     
mppe-stateless 
auth
require-chap
+chap
ms-dns 192.168.100.20
ms-wins 192.168.100.20

Config:
debug
option /etc/ppp/options.pptp
localip  192.168.100.181-190
remoteip 192.168.100.191-200

logs:
Feb 12 16:31:03 gateway pppd[29779]: MSCHAP-v2 peer authentication
succeeded for xxxxxx
Feb 12 16:31:03 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:03 gateway pppd[29779]: Protocol-Reject for unsupported
protocol 0x4c6f
Feb 12 16:31:03 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:03 gateway pppd[29779]: Protocol-Reject for unsupported
protocol 0x47
Feb 12 16:31:03 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:03 gateway pppd[29779]: Protocol-Reject for unsupported
protocol 0x47
Feb 12 16:31:03 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:03 gateway pppd[29779]: Protocol-Reject for unsupported
protocol 0x47
Feb 12 16:31:03 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:03 gateway pppd[29779]: Protocol-Reject for unsupported
protocol 0x47
Feb 12 16:31:03 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:03 gateway pppd[29779]: Protocol-Reject for unsupported
protocol 0x47
Feb 12 16:31:03 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:03 gateway pppd[29779]: Protocol-Reject for unsupported
protocol 0x47
Feb 12 16:31:03 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:03 gateway pppd[29779]: Protocol-Reject for unsupported
protocol 0x47
Feb 12 16:31:03 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:03 gateway pppd[29779]: Protocol-Reject for unsupported
protocol 0x47
Feb 12 16:31:03 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:03 gateway pppd[29779]: Protocol-Reject for unsupported
protocol 0x47
Feb 12 16:31:03 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:03 gateway pppd[29779]: Protocol-Reject for unsupported
protocol 0x47
Feb 12 16:31:03 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:06 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:06 gateway pptpd[29760]: CTRL: Ignored a SET LINK INFO
packet with real ACCMs!
Feb 12 16:31:06 gateway kernel: ip_demasq_gre(): xxx.xxx.xxx.xxx ->
xxx.xxx.xxx.xxx CID=0 no masq table, discarding 
Feb 12 16:31:06 gateway pppd[29779]: LCP terminated by peer
(C^Yg^T^@<M-Mt^@^@^C^J)
Feb 12 16:31:06 gateway pptpd[29760]: CTRL: Error with select(),
quitting
Feb 12 16:31:06 gateway pptpd[29760]: CTRL: Client xxx.xxx.xxx.xxx
control connection finished
Feb 12 16:31:06 gateway pppd[29779]: Modem hangup
Feb 12 16:31:06 gateway pppd[29779]: Connection terminated.
Feb 12 16:31:06 gateway pppd[29779]: Connect time 0.2 minutes.
Feb 12 16:31:06 gateway pppd[29779]: Sent 2454 bytes, received 930
bytes.
Feb 12 16:31:06 gateway pppd[29779]: Exit.






Regards 
Mark Burring
Systems Engineer (Internet) 
Deeptech - Intelligent Networking
Deepcare - Caring For Your IT Investment
Email:markb at deeptech.com.au
Web: www.deeptech.com.au ;www.deepcareonline.com
Phone: 1300 361 954 Fax: +61 8 9201 2312 
Postal: PO BOX 1324, West Perth WA 6872 
After hours Support: 1300 361 954