# pptpclient: LCP: timeout sending Config-Requests

## VinzC

Hi.

It's been two years I've been trying to setup a working VPN between a remote office and my home, unsuccessfully. I've always been unsuccessful in having a Gentoo VPN server (configured with pptp) and any Linux client connect together. Of course - as usual frustration - Windows clients connect easily and flawlessly.

Here's the plot.

A. VPN Server:

- Gentoo Linux (up to date)

- Behind a belkin firewall/wireless/adsl with NAT

- Running pptpd-1.3.4 and ppp-2.4.4-r9

- Gentoo kernel sources 2.6.18-r4

- Loaded modules: ppp-mppe, ppp-async, ppp-generic, ip-gre

- Service /etc/init.d/pptpd started

B. VPN Client 1

- Gentoo Linux (up to date)

- Intel Core2 Duo

- Behind a Gentoo Linux firewall/Home Router with NAT (iptables)

- Running ppp-2.4.4-r9, pptpclient-1.7.1-r1

- Gentoo kernel sources 2.6.21-r4

- Loaded modules: ppp-mppe, ppp-async, ppp-generic, ip-gre

- Connecting using pon command.

Running pon <mytunnel> debug dump logfd 2 nodetach gives the following output:

```
pppd options in effect:

debug           # (from command line)

nodetach                # (from command line)

logfd 2         # (from command line)

dump            # (from command line)

noauth          # (from /etc/ppp/options.pptp)

refuse-chap             # (from /etc/ppp/options.pptp)

refuse-mschap           # (from /etc/ppp/options.pptp)

refuse-eap              # (from /etc/ppp/options.pptp)

name user               # (from /etc/ppp/peers/mytunnel)

remotename mytunnel          # (from /etc/ppp/peers/mytunnel)

                # (from /etc/ppp/options.pptp)

pty pptp <vpn server internet address> --nolaunchpppd                # (from /etc/ppp/peers/mytunnel)

mru 1404                # (from /etc/ppp/options.pptp)

mtu 1400                # (from /etc/ppp/options.pptp)

ipparam mytunnel             # (from /etc/ppp/peers/mytunnel)

usepeerdns              # (from /etc/ppp/peers/mytunnel)

nobsdcomp               # (from /etc/ppp/options.pptp)

nodeflate               # (from /etc/ppp/options.pptp)

require-mppe-128                # (from /etc/ppp/options.pptp)

using channel 5

Using interface ppp0

Connect: ppp0 <--> /dev/pts/4

sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0x8adec9f2> <pcomp> <accomp>]

sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0x8adec9f2> <pcomp> <accomp>]

sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0x8adec9f2> <pcomp> <accomp>]

sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0x8adec9f2> <pcomp> <accomp>]

sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0x8adec9f2> <pcomp> <accomp>]

sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0x8adec9f2> <pcomp> <accomp>]

sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0x8adec9f2> <pcomp> <accomp>]

sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0x8adec9f2> <pcomp> <accomp>]

sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0x8adec9f2> <pcomp> <accomp>]

sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0x8adec9f2> <pcomp> <accomp>]

LCP: timeout sending Config-Requests

Connection terminated.

Modem hangup

Waiting for 1 child processes...
```

And in the VPN client's log file:

```
Aug  4 00:21:22 solo pppd[13847]: Using interface ppp0

Aug  4 00:21:22 solo pppd[13847]: Connect: ppp0 <--> /dev/pts/4

Aug  4 00:21:22 solo pptp[13848]: anon log[main:pptp.c:272]: The synchronous pptp option is NOT activated

Aug  4 00:21:22 solo pptp[13852]: anon log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 1 'Start-Control-Connection-Requ

est'

Aug  4 00:21:22 solo pptp[13852]: anon log[ctrlp_disp:pptp_ctrl.c:738]: Received Start Control Connection Reply

Aug  4 00:21:22 solo pptp[13852]: anon log[ctrlp_disp:pptp_ctrl.c:772]: Client connection established.

Aug  4 00:21:23 solo pppd[13847]: sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0xa96aecb3> <pcomp> <accomp>]

Aug  4 00:21:23 solo pptp[13852]: anon log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 7 'Outgoing-Call-Request'

Aug  4 00:21:23 solo pptp[13852]: anon log[ctrlp_disp:pptp_ctrl.c:857]: Received Outgoing Call Reply.

Aug  4 00:21:23 solo pptp[13852]: anon log[ctrlp_disp:pptp_ctrl.c:896]: Outgoing call established (call ID 0, peer's call ID 1152).

Aug  4 00:21:26 solo pppd[13847]: sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0xa96aecb3> <pcomp> <accomp>]

Aug  4 00:21:29 solo pppd[13847]: sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0xa96aecb3> <pcomp> <accomp>]

Aug  4 00:21:32 solo pppd[13847]: sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0xa96aecb3> <pcomp> <accomp>]

Aug  4 00:21:35 solo pppd[13847]: sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0xa96aecb3> <pcomp> <accomp>]

Aug  4 00:21:38 solo pppd[13847]: sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0xa96aecb3> <pcomp> <accomp>]

Aug  4 00:21:41 solo pppd[13847]: sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0xa96aecb3> <pcomp> <accomp>]

Aug  4 00:21:44 solo pppd[13847]: sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0xa96aecb3> <pcomp> <accomp>]

Aug  4 00:21:47 solo pppd[13847]: sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0xa96aecb3> <pcomp> <accomp>]

Aug  4 00:21:50 solo pppd[13847]: sent [LCP ConfReq id=0x1 <mru 1404> <asyncmap 0x0> <magic 0xa96aecb3> <pcomp> <accomp>]

Aug  4 00:21:53 solo pppd[13847]: LCP: timeout sending Config-Requests

Aug  4 00:21:53 solo pppd[13847]: Connection terminated.

Aug  4 00:21:53 solo pppd[13847]: Modem hangup
```

Here's what I have on the VPN server's log:

```
Aug  4 00:21:22 serenity pptpd[27242]: CTRL: Client 62.197.114.x control connection started

Aug  4 00:21:23 serenity pptpd[27242]: CTRL: Starting call (launching pppd, opening GRE)

Aug  4 00:21:23 serenity pppd[27243]: Plugin /usr/lib/pptpd/pptpd-logwtmp.so loaded.

Aug  4 00:21:23 serenity pppd[27243]: pppd 2.4.4 started by root, uid 0

Aug  4 00:21:23 serenity pppd[27243]: Using interface ppp0

Aug  4 00:21:23 serenity pppd[27243]: Connect: ppp0 <--> /dev/pts/1

Aug  4 00:21:53 serenity pppd[27243]: Modem hangup

Aug  4 00:21:53 serenity pppd[27243]: Connection terminated.

Aug  4 00:21:53 serenity pptpd[27242]: CTRL: Reaping child PPP[27243]

Aug  4 00:21:53 serenity pppd[27243]: Exit.

Aug  4 00:21:53 serenity pptpd[27242]: CTRL: Client 62.197.114.x control connection finished
```

The IP address 62.197.114.x is my home router's public IP address.

I've run tcpdump on both the VPN server and my home router. If I have correctly understood the traffic, it looks like the VPN server does send LCP config packets but my home router doesn't see them. Also my pptp client sends LCP packets but it looks like they're not received by the VPN server.

I've also tried Ubuntu 7.04 as a pptp client with the exact same configuration (and the same packages). Same problem.

Frankly, if it works with Window$ clients, why the heck doesn't it work with Linux clients? Windows clients also use GRE (I've seen GRE traffic on the VPN server's side).

Can anyone tell me what's wrong in that process? Can anyone tell me how I can get more info from that system so I can dig any further?

I'd like not to spend another two years in vain. I want (to be able to find) an explanation on what's going wrong; and it's been two years I'm struggling, not being able to find what's wrong.

Thanks a LOT in advance for any light, help, hint, info, whatever.

----------

