pptp gre in csf firewall

Question

i have a senior problem. when i want to connecting a pptp over a tap adaptor or a pptp connection have get disconnected and get this errors on messages logs:

linux pptpd[20275]: GRE: read(fd=7,buffer=60a400,len=8260) from network failed: status = -1 error = Message too long
linux pptpd[20275]: CTRL: GRE read or PTY write failed (gre,pty)=(7,6)
linux pppd[20276]: Modem hangup
linux pppd[20276]: Connect time 0.2 minutes.
linux pppd[20276]: Sent 15948 bytes, received 11596 bytes.
linux pppd[20276]: MPPE disabled
linux pppd[20276]: Connection terminated.
linux pppd[20276]: Exit.
linux pptpd[20275]: CTRL: Client xx.xx.xx.xx control connection finished

in order my firewall is CSF add i inserted these rules in csfpre.sh :

iptables -A INPUT -i eth0 -p tcp --dport 1723 -j ACCEPT
iptables -A INPUT -i eth0 -p gre -j ACCEPT
iptables -A OUTPUT -p gre -j ACCEPT
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A FORWARD -i ppp+ -o eth0 -j ACCEPT
iptables -A FORWARD -i eth0 -o ppp+ -j ACCEPT

but nothing changed and the above problem exist. thanks

Try inserting the rules, not adding them. So, `iptables -I INPUT`, etc. You have some conflicting rules in the firewall. So, for example if you have a rule to drop everything on port 1723, that will be processed first and your rule accepting traffic on eth0 to that port will not be actually processed. — Mugurel, Aug 26 '16 at 10:49

score 0 · Answer 1 · answered Aug 26 '16 at 15:37

0

fortunately, problem has been solved with add

mru 900
mtu 900

in options.pptp

answered Aug 26 '16 at 15:37

alireza m

13
1
7

I would choose some values that aren't going to cause breakage once the ISP gets around to upgrade the connection to IPv6. The IPv6 standard requires at least 1280, and the connection will probably work with values up to 1492. – kasperd Aug 26 '16 at 18:29

pptp gre in csf firewall

1 Answers1