How to push emails through GRE

Comments

• agentsmith Member

  February 2015 edited February 2015

  so you want to route (layer 3) something into the gre tunnel or you want to use a proxy (layer 7)?
• PrincessOfCats Member

  February 2015 edited February 2015

  Either one will work - whichever one is easier. I just want to make the IP that shows up in the mandrill email header the one from the GRE host so that I don't leak my non-ddos protected IP out in emails.

  Edit: removed GRE proxy from the first post - its a GRE tunnel not a proxy
• sonontse Member

  February 2015

  Setup a postfix server with mandrill on your server with the public facing IP. On your gitlab server, smtp your emails to that postfix server.
• agentsmith Member

  February 2015 edited February 2015

  so i would prefer routing:

  ip r a default via <remote tunnel ip> ta 2
  ip ru a fwmark 0x2 ta 2
  iptables -t mangle -A OUTPUT -p tcp --dport 25 -j MARK --fwmark 0x2
  iptables -t mangle -A POSTROUTING -p tcp --dport 25 -o eth0 -j DROP
  

  on the remote side:

  iptables -t nat -A POSTROUTING -s <tunnel ip> -j MASQUERADE
  echo 1 > /proc/sys/net/ipv4/ip_forward
  

  without testing anything...