All NordVPN ports are open on our servers for outgoing connections, except SMTP and Netbios. Since we do not provide any port-forwarding, no incoming connections can go through.
SMTP (Simple Mail Transfer Protocol) is a technical standard for transmitting emails over a network. In case you're facing issues with mailing, you can change your SMTP outgoing port to 465 or 587 ports instead.
In case you have an additional firewall set up and internet speed gets better when you turn it off while you're connected to NordVPN - you can change the outgoing ports on your firewall so that the VPN and your firewall do not clash. You can use one of the following open ports after choosing what NordVPN protocol you want to use:
- OpenVPN TCP: 443, 1231-1234;
- OpenVPN UDP: UDP 1194, 1231-1234;
- IKEv2: UDP 500 + UDP 4500 (before a NAT firewall), or UDP 500 + TCP 4500 (after a NAT firewall);
- NordLynx: UDP 51820;
- SOCKS5 proxy: UDP 1080 or TCP 1080.