[pptp-server] I don't understand anything ! :-)

Javier Cuevas jcd at arrakis.es
Thu Jan 11 16:35:09 CST 2001


Hello,

 I already configured a network like this:

  First Case  diagram:

  Computer A
/---------\                         Computer B
 |----------|                         /
\                       |------------|
 |  Linux   |                        /  Intranet
\                      |   Win98    |
 |  Server  |--eth0(192.168.25.5)---/ 192.168.25.0
\------(192.168.25.3)-| vpn client |
 |  (pptpd) |                       \
/                     |   DUN 1.3  |
 |----------|                        \
/                      |----------- |
          \
\-----------/                         /

\                                                               /

\                                                             /

\-----------------------------------------------------------/
                                                         Tunnel
established Ok (with mppe and mschap-v2)

  Second Case diagram:

  Computer A
/---------\                            Computer B
 |----------|                            /
\                         |------------|
 |  Linux   |  ISDN line                /  Internet   \
phone line |   Win98    |
 |  Server  |--ppp0(194.143.220.184)---/
\---(194.143.193.61)ppp-| vpn client |
 |  (pptpd) |                          \
/                       |   DUN 1.3  |
 |----------|                           \
/                        |----------- |
          \
\-----------/                            /

\                                                                     /

\                                                                   /
             \--------------------------/error
/-------------------------------/
                                             Tunnel fails. Client try to
connect but fails... :-???? why?


-  Computer's software :

  On Computer A:
     - Linux RedHat 7.0
     - kernel 2.2.16
     - pppd   2.3.11
     - pptpd  1.0.1
     - patch for mppe and mschap-v2

  On Computer B:
     - Microsoft Windows 98
     - DUN 1.3

- Fisrt case description:
  =======================

The two computers are at the same local ethernet network (net
192.168.25.0/24). Ok ?


I sucessfully configured the Linux pptpd server on Computer A and also
the Win98 Vpn
client. And I can successfully make the tunnel with compresion an
encryption.


I add a ISDN card to the Linux Computer to connect the intranet to
Intenet with ipchains and
masquerading.
I sucessfully configured de ISDN card to connect to my ISP. Now the
server can Access to
Internet( great! ;-)

Now I want to connect to my pptp server from internet. Ok. I change my
pptpd configurations
file to attach the server to the new ppp0 internet interface (with a
fixed ip).

I use my Laptop to connect to internet via modem. My Laptop is not
connected to my Intranet.
I configure the w98 Vpn client as I do in Computer B. I try to connect
to my pptp server and
I can't. It fails :-(. Why?.

I log all traffic on interfaces eth0 and ppp0 with ipchains to view
what's happend.

I Paste the portions of log's in both cases.

- First Case log's lines (connection made from intranet):

-----------------------8<----------8<----------8<----------8<----------8<----------8<

Jan 11 18:51:13 firewall pptpd[11196]: CTRL: Client 192.168.25.3 control
connection started
Jan 11 18:51:13 firewall kernel: Packet log: output ACCEPT eth0 PROTO=6
192.168.25.5:1723 192.168.25.3:1107 L=196 S=0x00 I=308 F=0x0000 T=64
(#2)
Jan 11 18:51:13 firewall kernel: Packet log: input ACCEPT eth0 PROTO=6
192.168.25.3:1107 192.168.25.5:1723 L=208 S=0x00 I=56325 F=0x4000 T=128
(#2)
Jan 11 18:51:13 firewall kernel: Packet log: output ACCEPT eth0 PROTO=6
192.168.25.5:1723 192.168.25.3:1107 L=40 S=0x00 I=309 F=0x0000 T=64 (#2)

Jan 11 18:51:13 firewall pptpd[11196]: CTRL: Starting call (launching
pppd, opening GRE)
Jan 11 18:51:13 firewall kernel: Packet log: output ACCEPT eth0 PROTO=6
192.168.25.5:1723 192.168.25.3:1107 L=72 S=0x00 I=310 F=0x0000 T=64 (#2)

Jan 11 18:51:13 firewall pppd[11197]: pppd 2.3.11 started by root, uid 0

Jan 11 18:51:13 firewall pppd[11197]: Using interface ppp1
Jan 11 18:51:13 firewall pppd[11197]: Connect: ppp1 <--> /dev/pts/4
Jan 11 18:51:13 firewall kernel: Packet log: input ACCEPT eth0 PROTO=47
192.168.25.3:65535 192.168.25.5:65535 L=50 S=0x00 I=56581 F=0x0000 T=128
(#2)
Jan 11 18:51:13 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=61 S=0x00 I=311 F=0x0000 T=64
(#2)
Jan 11 18:51:13 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=32 S=0x00 I=312 F=0x0000 T=64
(#2)
Jan 11 18:51:13 firewall kernel: Packet log: input ACCEPT eth0 PROTO=6
192.168.25.3:1107 192.168.25.5:1723 L=40 S=0x00 I=56837 F=0x4000 T=128
(#2)
Jan 11 18:51:13 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=50 S=0x00 I=313 F=0x0000 T=64
(#2)
Jan 11 18:51:13 firewall kernel: Packet log: input ACCEPT eth0 PROTO=47
192.168.25.3:65535 192.168.25.5:65535 L=65 S=0x00 I=57093 F=0x0000 T=128
(#2)
Jan 11 18:51:13 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=32 S=0x00 I=314 F=0x0000 T=64
(#2)
Jan 11 18:51:13 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=58 S=0x00 I=315 F=0x0000 T=64
(#2)
Jan 11 18:51:13 firewall kernel: Packet log: input ACCEPT eth0 PROTO=47
192.168.25.3:65535 192.168.25.5:65535 L=105 S=0x00 I=57349 F=0x0000
T=128 (#2)
Jan 11 18:51:13 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=32 S=0x00 I=316 F=0x0000 T=64
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=80 S=0x00 I=317 F=0x0000 T=64
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=50 S=0x00 I=318 F=0x0000 T=64
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: input ACCEPT eth0 PROTO=47
192.168.25.3:65535 192.168.25.5:65535 L=78 S=0x00 I=57605 F=0x0000 T=128
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=32 S=0x00 I=319 F=0x0000 T=64
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: input ACCEPT eth0 PROTO=47
192.168.25.3:65535 192.168.25.5:65535 L=50 S=0x00 I=57861 F=0x0000 T=128
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=32 S=0x00 I=320 F=0x0000 T=64
(#2)
Jan 11 18:51:14 firewall kernel: PPP BSD Compression module registered
Jan 11 18:51:14 firewall kernel: PPP MPPE compression module registered
Jan 11 18:51:14 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=55 S=0x00 I=321 F=0x0000 T=64
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: input ACCEPT eth0 PROTO=47
192.168.25.3:65535 192.168.25.5:65535 L=67 S=0x00 I=58117 F=0x0000 T=128
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=32 S=0x00 I=322 F=0x0000 T=64
(#2)
Jan 11 18:51:14 firewall pppd[11197]: MSCHAP-v2 peer authentication
succeeded for PROYECTOS\\web
Jan 11 18:51:14 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=50 S=0x00 I=323 F=0x0000 T=64
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: input ACCEPT eth0 PROTO=47
192.168.25.3:65535 192.168.25.5:65535 L=66 S=0x00 I=58373 F=0x0000 T=128
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=32 S=0x00 I=324 F=0x0000 T=64
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=56 S=0x00 I=325 F=0x0000 T=64
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: input ACCEPT eth0 PROTO=47
192.168.25.3:65535 192.168.25.5:65535 L=66 S=0x00 I=58629 F=0x0000 T=128
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=32 S=0x00 I=326 F=0x0000 T=64
(#2)
Jan 11 18:51:14 firewall pppd[11197]: found interface eth0 for proxy arp

Jan 11 18:51:14 firewall pppd[11197]: local  IP address 192.168.25.30
Jan 11 18:51:14 firewall pppd[11197]: remote IP address 192.168.25.231
Jan 11 18:51:14 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=62 S=0x00 I=327 F=0x0000 T=64
(#2)
Jan 11 18:51:14 firewall kernel: Packet log: input ACCEPT eth0 PROTO=47
192.168.25.3:65535 192.168.25.5:65535 L=32 S=0x00 I=58885 F=0x0000 T=128
(#2)
Jan 11 18:51:15 firewall kernel: Packet log: input ACCEPT eth0 PROTO=47
192.168.25.3:65535 192.168.25.5:65535 L=61 S=0x00 I=59397 F=0x0000 T=128
(#2)
Jan 11 18:51:15 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=32 S=0x00 I=328 F=0x0000 T=64
(#2)
Jan 11 18:51:17 firewall kernel: Packet log: input ACCEPT eth0 PROTO=17
192.168.25.1:1025 192.168.25.255:2071 L=104 S=0x00 I=33051 F=0x0000 T=64
(#2)
Jan 11 18:51:18 firewall kernel: Packet log: input ACCEPT eth0 PROTO=47
192.168.25.3:65535 192.168.25.5:65535 L=61 S=0x00 I=59909 F=0x0000 T=128
(#2)
Jan 11 18:51:18 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=32 S=0x00 I=329 F=0x0000 T=64
(#2)
Jan 11 18:51:19 firewall kernel: Packet log: input ACCEPT eth0 PROTO=47
192.168.25.3:65535 192.168.25.5:65535 L=40 S=0x00 I=60165 F=0x0000 T=128
(#2)
Jan 11 18:51:19 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=32 S=0x00 I=330 F=0x0000 T=64
(#2)
Jan 11 18:51:19 firewall pppd[11197]: LCP terminated by peer
Jan 11 18:51:19 firewall kernel: Packet log: output ACCEPT eth0 PROTO=47
192.168.25.5:65535 192.168.25.3:65535 L=40 S=0x00 I=331 F=0x0000 T=64
(#2)
Jan 11 18:51:19 firewall kernel: Packet log: input ACCEPT eth0 PROTO=6
192.168.25.3:1107 192.168.25.5:1723 L=56 S=0x00 I=60421 F=0x4000 T=128
(#2)
Jan 11 18:51:19 firewall pptpd[11196]: CTRL: Error with select(),
quitting
Jan 11 18:51:19 firewall pptpd[11196]: CTRL: Client 192.168.25.3 control
connection finished
Jan 11 18:51:19 firewall kernel: Packet log: output ACCEPT eth0 PROTO=6
192.168.25.5:1723 192.168.25.3:1107 L=188 S=0x00 I=332 F=0x0000 T=64
(#2)
Jan 11 18:51:19 firewall kernel: Packet log: output ACCEPT eth0 PROTO=6
192.168.25.5:1723 192.168.25.3:1107 L=40 S=0x00 I=333 F=0x0000 T=64 (#2)

Jan 11 18:51:19 firewall kernel: Packet log: input ACCEPT eth0 PROTO=6
192.168.25.3:1107 192.168.25.5:1723 L=40 S=0x00 I=60677 F=0x4000 T=128
(#2)
Jan 11 18:51:19 firewall kernel: Packet log: output ACCEPT eth0 PROTO=6
192.168.25.5:1723 192.168.25.3:1107 L=40 S=0x00 I=334 F=0x0000 T=64 (#2)

Jan 11 18:51:19 firewall pppd[11197]: Modem hangup
Jan 11 18:51:19 firewall pppd[11197]: Connection terminated.
Jan 11 18:51:19 firewall pppd[11197]: Connect time 0.1 minutes.
Jan 11 18:51:19 firewall pppd[11197]: Sent 381 bytes, received 577
bytes.
Jan 11 18:51:19 firewall pppd[11197]: Exit.
-----------------------8<----------8<----------8<----------8<----------8<----------8<



- Second Case log's lines (connection made from Internet):
-----------------------8<----------8<----------8<----------8<----------8<----------8<

Jan 11 18:43:32 firewall pptpd[9443]: CTRL: Client 194.143.193.61
control connection started
Jan 11 18:43:32 firewall kernel: Packet log: input ACCEPT ppp0 PROTO=6
194.143.193.61:1105 194.143.220.184:1723 L=196 S=0x00 I=50949 F=0x4000
T=127 (#2)
Jan 11 18:43:32 firewall kernel: Packet log: output ACCEPT ppp0 PROTO=6
194.143.220.184:1723 194.143.193.61:1105 L=40 S=0x00 I=294 F=0x0000 T=64
(#2)
Jan 11 18:43:32 firewall kernel: Packet log: output ACCEPT ppp0 PROTO=6
194.143.220.184:1723 194.143.193.61:1105 L=196 S=0x00 I=295 F=0x0000
T=64 (#2)
Jan 11 18:43:32 firewall kernel: Packet log: input ACCEPT ppp0 PROTO=6
194.143.193.61:1105 194.143.220.184:1723 L=208 S=0x00 I=51205 F=0x4000
T=127 (#2)
Jan 11 18:43:32 firewall pptpd[9443]: CTRL: Starting call (launching
pppd, opening GRE)
Jan 11 18:43:32 firewall kernel: Packet log: output ACCEPT ppp0 PROTO=6
194.143.220.184:1723 194.143.193.61:1105 L=72 S=0x00 I=296 F=0x0000 T=64
(#2)
Jan 11 18:43:32 firewall pppd[9444]: pppd 2.3.11 started by root, uid 0
Jan 11 18:43:32 firewall pppd[9444]: Using interface ppp1
Jan 11 18:43:32 firewall pppd[9444]: Connect: ppp1 <--> /dev/pts/4
Jan 11 18:43:32 firewall kernel: Packet log: output ACCEPT ppp0 PROTO=47
194.143.220.184:65535 194.143.193.61:65535 L=61 S=0x00 I=297 F=0x0000
T=64 (#2)
Jan 11 18:43:32 firewall kernel: Packet log: input ACCEPT ppp0 PROTO=6
194.143.193.61:1105 194.143.220.184:1723 L=40 S=0x00 I=51461 F=0x4000
T=127 (#2)
Jan 11 18:43:33 firewall kernel: Packet log: input ACCEPT ppp0 PROTO=47
194.143.193.61:65535 194.143.220.184:65535 L=32 S=0x00 I=51717 F=0x0000
T=127 (#2)
Jan 11 18:43:35 firewall kernel: Packet log: output ACCEPT ppp0 PROTO=47
194.143.220.184:65535 194.143.193.61:65535 L=61 S=0x00 I=298 F=0x0000
T=64 (#2)
Jan 11 18:43:35 firewall kernel: Packet log: input ACCEPT ppp0 PROTO=6
194.143.193.61:1105 194.143.220.184:1723 L=56 S=0x00 I=51973 F=0x4000
T=127 (#2)
Jan 11 18:43:35 firewall kernel: Packet log: output ACCEPT ppp0 PROTO=6
194.143.220.184:1723 194.143.193.61:1105 L=188 S=0x00 I=299 F=0x0000
T=64 (#2)
Jan 11 18:43:35 firewall pppd[9444]: Modem hangup
Jan 11 18:43:35 firewall pppd[9444]: Connection terminated.
Jan 11 18:43:35 firewall pppd[9444]: Exit.
Jan 11 18:43:35 firewall pptpd[9443]: CTRL: Error with select(),
quitting
Jan 11 18:43:35 firewall pptpd[9443]: CTRL: Client 194.143.193.61
control connection finished
-----------------------8<----------8<----------8<----------8<----------8<----------8<



How we can see, some packets are lost. Why? What's the problem?

Can anybody help me.

Thanks.

Javier Cuevas.
jcd at arrakis.es





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