Topic: Quick advice on VPN/PPTP session logout

[gbentley]

Hi All,

I have setup routers on many occasions for VPN to SME however this one is causing a few problems. Its a BT Voyager 220v. In service you choose from the drop down list 'VPN' and this creates enteries for pptp and gre. Thats it (so the userguide says!) It should be ready to go.

What happens is, I get a login but as soon as I try and pass any data I get logged out. Odd. Heres a session log. Any thoughts etcappreciated.

Apr 19 09:39:27 server pptpd[15641]: CTRL: Client 81.174.174.115 control connection finished
Apr 19 09:39:31 server pptpd[16007]: CTRL: Client 81.174.174.115 control connection started
Apr 19 09:39:31 server pptpd[16007]: CTRL: Starting call (launching pppd, opening GRE)
Apr 19 09:39:31 server pppd[16008]: Plugin radius.so loaded.
Apr 19 09:39:31 server pppd[16008]: RADIUS plugin initialized.
Apr 19 09:39:31 server pppd[16008]: pppd 2.4.4 started by root, uid 0
Apr 19 09:39:31 server kernel: divert: not allocating divert_blk for non-ethernet device ppp0
Apr 19 09:39:31 server pppd[16008]: Using interface ppp0
Apr 19 09:39:31 server pppd[16008]: Connect: ppp0 <--> /dev/pts/0
Apr 19 09:39:31 server pptpd[16007]: CTRL: Ignored a SET LINK INFO packet with real ACCMs!
Apr 19 09:39:31 server pppd[16008]: MPPE 128-bit stateless compression enabled
Apr 19 09:39:33 server pppd[16008]: found interface eth0 for proxy arp
Apr 19 09:39:33 server pppd[16008]: local  IP address 192.168.0.1
Apr 19 09:39:33 server pppd[16008]: remote IP address 192.168.0.249
Apr 19 09:39:33 server esmith::event[16032]: Processing event: ip-up.pptpd ppp0 /dev/pts/0 460800 192.168.0.1 192.168.0.249 pptpd
Apr 19 09:39:33 server esmith::event[16032]: Running event handler: /etc/e-smith/events/actions/generic_template_expand
Apr 19 09:39:34 server esmith::event[16032]: expanding /etc/rc.d/init.d/masq  
Apr 19 09:39:34 server esmith::event[16032]: generic_template_expand=action|Event|ip-up.pptpd|Action|generic_template_expand|Start|1176971973 913920|End|1176971974 314720|Elapsed|0.4008
Apr 19 09:39:34 server esmith::event[16032]: Running event handler: /etc/e-smith/events/ip-up.pptpd/S70pptp-interface-access
Apr 19 09:39:34 server /etc/e-smith/events/ip-up.pptpd/S70pptp-interface-access[16034]: /home/e-smith/db/configuration: OLD pptpd=service|Interfaces||TCPPort|1723|access|public|sessions|2|status|enabled
Apr 19 09:39:34 server /etc/e-smith/events/ip-up.pptpd/S70pptp-interface-access[16034]: /home/e-smith/db/configuration: NEW pptpd=service|Interfaces|ppp0|TCPPort|1723|access|public|sessions|2|status|enabled
Apr 19 09:39:34 server esmith::event[16032]: S70pptp-interface-access=action|Event|ip-up.pptpd|Action|S70pptp-interface-access|Start|1176971974 315147|End|1176971974 473007|Elapsed|0.15786
Apr 19 09:39:34 server esmith::event[16032]: Running event handler: /etc/e-smith/events/actions/adjust-services
Apr 19 09:39:34 server esmith::event[16032]: adjusting non-supervised masq (adjust)  
Apr 19 09:39:34 server esmith::event[16032]: adjust-services=action|Event|ip-up.pptpd|Action|adjust-services|Start|1176971974 473472|End|1176971974 968297|Elapsed|0.494825
Apr 19 09:39:43 server pptpd[16007]: GRE: read(fd=7,buffer=8056c40,len=8260) from network failed: status = -1 error = Message too long
Apr 19 09:39:43 server pptpd[16007]: CTRL: GRE read or PTY write failed (gre,pty)=(7,6)
Apr 19 09:39:43 server pptpd[16007]: CTRL: Reaping child PPP[16008]
Apr 19 09:39:43 server pppd[16008]: Modem hangup
Apr 19 09:39:43 server pppd[16008]: Connect time 0.2 minutes.
Apr 19 09:39:43 server pppd[16008]: Sent 5999 bytes, received 3974 bytes.
Apr 19 09:39:43 server pppd[16008]: MPPE disabled
Apr 19 09:39:43 server pppd[16008]: Connection terminated.

[CharlieBrady]

I have setup routers on many occasions for VPN to SME however this one is causing a few problems. Its a BT Voyager 220v. In service you choose from the drop down list 'VPN' and this creates enteries for pptp and gre.
...
What happens is, I get a login but as soon as I try and pass any data I get logged out. Odd. Heres a session log. Any thoughts etcappreciated.
...
Apr 19 09:39:43 server pptpd[16007]: GRE: read(fd=7,buffer=8056c40,len=8260) from network failed: status = -1 error = Message too long

Use google to read up on MSS clamping, DF and fragmentation required. You might be able to work around the problem by adjusting MTU somewhere.

[gbentley]

Thanks Charlie, I increased the MTU setting and now all works !

Regards

Graham

ps That'll be 2000 and 1 beers I owe you !!!

[CharlieBrady]

ps That'll be 2000 and 1 beers I owe you !!!

Or a new cricket bat

[tspoon1986]

Hi, I'm getting a similar entry in my logs as above. Where did you change the MTU, on the router or on SME? If SME, can you tell me how you did it? What size did you change it to?

Thanks for your help.

[byte]

Hi, I'm getting a similar entry in my logs as above. Where did you change the MTU,

You can change MTU and/or MRU by using the following:

db configuration setprop pptpd mru xxxx
db configuration setprop pptpd mtu xxxx
signal-event remoteaccess-update

where xxxx is the value you wish to change, it does normally depend on your ISP what mtu value is needed.