With the following machines...
Server 1: PPTP client windows; Public IP: 1.1.1.1
Server 3: PPTP server centos6; Public IP: 3.3.3.3
Connecting VPN server3 from server1 works correctly!
Goal is to have a middle server forwarding traffic in both ways
Server 1: PPTP client windows; Public IP: 1.1.1.1
Server 2: Traffic forwarding centos6; Public IP: 2.2.2.2
Server 3: PPTP server centos6; Public IP: 3.3.3.3
Server1 connects with PPTP client to 2.2.2.2 and this server2 redirects to 3.3.3.3 (server3)
Is it possible to have that scenario?
Tried the following setup in Server2
- Routing enabled
# echo "1" > /proc/sys/net/ipv4/ip_forward
# nano /etc/sysctl.conf
net.ipv4.ip_forward = 1
# sysctl -p
- Iptables forward
# iptables -F -t nat
# iptables -F
# iptables -A FORWARD -d 3.3.3.3 -i eth0 -j ACCEPT
# iptables -t nat -A PREROUTING -i eth0 -d 2.2.2.2 -j DNAT --to-destination 3.3.3.3
# iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
# iptables save
# iptables reload
When trying to connect with Server1 VPN PPTP client to 2.2.2.2, it redirects correctly to 3.3.3.3.
However, in server3 (3.3.3.3) it does not assign a PPTP client to 2.2.2.2.
Here is the connection log at server3
# tail -f /var/log/messages
Nov 29 09:53:39 office pptpd[2121]: CTRL: Client 2.2.2.2 control connection started
Nov 29 09:53:39 office pptpd[2121]: CTRL: Starting call (launching pppd, opening GRE)
Nov 29 09:53:39 office pppd[2122]: Plugin /usr/lib64/pptpd/pptpd-logwtmp.so loaded.
Nov 29 09:53:39 office pppd[2122]: pppd 2.4.5 started by root, uid 0
Nov 29 09:53:39 office pppd[2122]: Using interface ppp2
Nov 29 09:53:39 office pppd[2122]: Connect: ppp2 <--> /dev/pts/3
Nov 29 09:54:09 office pppd[2122]: LCP: timeout sending Config-Requests
Nov 29 09:54:09 office pppd[2122]: Connection terminated.
Nov 29 09:54:09 office pppd[2122]: Modem hangup
Nov 29 09:54:09 office pppd[2122]: Exit.
Nov 29 09:54:09 office pptpd[2121]: GRE: read(fd=6,buffer=6124a0,len=8196) from PTY failed: status = -1 error = Input/output error, usually caused by unexpected termination of pppd, check option syntax and pppd logs
Nov 29 09:54:09 office pptpd[2121]: CTRL: PTY read or GRE write failed (pty,gre)=(6,7)
Nov 29 09:54:09 office pptpd[2121]: CTRL: Client 2.2.2.2 control connection finished
Any ideas to setup the server2 working as middle traffic forwarder?