VPN-сервер не получается

Помогите пожалуйста настроить VPN-сервер.
Сервер имеет адрес 192.168.20.55, подключаюсь с 192.168.20.39

/etc/pptpd.conf:
---
option /etc/ppp/options.pptpd
localip 192.168.20.55
remoteip 192.168.20.39-75
debug
---

/etc/ppp/options.pptpd:
---
debug
name srv.czins.ru
auth
require-chap
proxyarp
192.168.20.20:192.168.20.50
---

В /etc/ppp/chap-secrets прописал:
_ЛОГИН) * _ПАРОЛЬ_ *

При подключении с виндов появляется табличка "Проверка имени пользователя и пароля" и висит до таймаута.

В логах читаю:
---
Jul 24 16:55:57 localhost pptpd[27672]: CTRL: Client 192.168.20.39 control connection started
Jul 24 16:55:57 localhost pptpd[27672]: CTRL: Starting call (launching pppd, opening GRE)
Jul 24 16:55:57 localhost pppd[27673]: pppd 2.4.2b3 started by root, uid 0
Jul 24 16:55:57 localhost pppd[27673]: Using interface ppp0
Jul 24 16:55:57 localhost pppd[27673]: Connect: ppp0 <--> /dev/pts/6
Jul 24 16:55:57 localhost pptpd[27672]: GRE: Discarding duplicate packet
Jul 24 16:55:57 localhost /etc/hotplug/net.agent: assuming ppp0 is already up
Jul 24 16:56:27 localhost pppd[27673]: LCP: timeout sending Config-Requests
Jul 24 16:56:27 localhost pppd[27673]: Connection terminated.
Jul 24 16:56:27 localhost pppd[27673]: Exit.
Jul 24 16:56:27 localhost pptpd[27672]: GRE: read(fd=5,buffer=804d580,len=8196) from PTY failed: status = -1 error = Input/output error
Jul 24 16:56:27 localhost pptpd[27672]: CTRL: PTY read or GRE write failed (pty,gre)=(5,6)
Jul 24 16:56:27 localhost pptpd[27672]: CTRL: Client 192.168.20.39 control connection finished
Jul 24 16:56:27 localhost /etc/hotplug/net.agent: NET unregister event not supported
---

Скажите, что не так?