All about VPN ports

1) If RRAS based VPN server is behind a firewall (i.e. a firewall is placed between Internet and RRAS server), then following ports need to be opened (bidirectional) on this firewall to allow VPN traffic to pass through: –

  1. For PPTP:
    1. IP Protocol=TCP, TCP Port number=1723   <- Used by PPTP control path
    2. IP Protocol=GRE (value 47)   <- Used by PPTP data path
  2. For L2TP:
    1. IP Protocol Type=UDP, UDP Port Number=500    <- Used by IKEv1 (IPSec control path)
    2. IP Protocol Type=UDP, UDP Port Number=4500   <- Used by IKEv1 (IPSec control path)
    3. IP Protocol Type=ESP (value 50)   <- Used by IPSec data path
  3. For SSTP:
    1. IP Protocol=TCP, TCP Port number=443   <- Used by SSTP control and data path
  4. For IKEv2:
    1. IP Protocol Type=UDP, UDP Port Number=500    <- Used by IKEv2 (IPSec control path)
    2. IP Protocol Type=UDP, UDP Port Number=4500   <- Used by IKEv2 (IPSec control path)
    3. IP Protocol Type=ESP (value 50)   <- Used by IPSec data path

2) If RRAS server is directly connected to Internet, then you need to protect RRAS server from the Internet side (i.e. only allow access to the services on the public interface that isaccessible from the Internet side).

  1. For PPTP:
    1. IP Protocol=TCP, TCP Port number=1723  <- Used by PPTP control path
    2. IP Protocol=GRE (value 47)  <- Used by PPTP data path
  2. For L2TP:
    1. IP Protocol Type=UDP, UDP Port Number=500   <- Used by IKEv1 (IPSec control path)
    2. IP Protocol Type=UDP, UDP Port Number=4500 <- Used by IKEv1 (IPSec control path)
    3. IP Protocol Type=UDP, UDP Port Number=1701  <- Used by L2TP control/data path
    4. IP Protocol Type=50  <- Used by data path (ESP)
  3. For SSTP:
    1. IP Protocol=TCP, TCP Port number=443   <- Used by SSTP control and data path
  4. For IKEv2:
    1. IP Protocol Type=UDP, UDP Port Number=500   <- Used by IKEv2 (IPSec control path)
    2. IP Protocol Type=UDP, UDP Port Number=4500 <- Used by IKEv2 (IPSec control path)
    3. IP Protocol Type=UDP, UDP Port Number=1701  <- Used by L2TP control/data path
    4. IP Protocol Type=50 <- Used by data path (ESP)
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