pptpd - какие порты открыть в iptables?

Захожу с винды с рабочей сетки - все ок.
Из дома - отлуп, в /var/log/messages следующее:
<pre>
pptpd[2367]: CTRL: Client 66.55.44.33 control connection started
pptpd[2367]: CTRL: Starting call (launching pppd, opening GRE)
pppd[2368]: pppd 2.4.1 started by root, uid 0
pppd[2368]: Using interface ppp0
pppd[2368]: Connect: ppp0 <--> /dev/pts/2
pptpd[2367]: GRE: read(fd=9,buffer=8055c20,len=8260) from network failed: status = -1 error = Protocol not available
pptpd[2367]: CTRL: GRE read or PTY write failed (gre,pty)=(9,8)
pppd[2368]: Modem hangup
pppd[2368]: Connection terminated.
pptpd[2367]: CTRL: Client 194.186.24.2 control connection finished
pppd[2368]: Terminating on signal 2.
pppd[2368]: Exit.
</pre>