Deliberant DLB21 Series, User Manual

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WAN.
Configuring Port Forwarding (Virtual Server)
This function allows you to automatically redirect common network services to a specific machine behind the NAT firewall.
These settings are only necessary if you wish to host some sort of server like a web server or mail server on the private local
network behind the device's NAT firewall.
The most often used port numbers are shown in the following table.
Services Port Number
ECHO 7
FTP (File Transfer Protocol)
21
Telnet 23
SMTP (Simple Mail Transfer Protocol)
25
DNS (Domain Name System) 53
Finger 79
HTTP (Hyper Text Transfer Protocol)
80
POP3 (Post Protocol) 110
NNTP (Network News Transport Protocol) 119
SNMP (Simple Network Management Protocol) 161
SNMP trap 162
SIP (Session Initiation Protocol) 5060
PPTP (Point-to-Point Tunneling Protocol) 1723
Multiple Servers behind NAT Example:
In this case, there are two PCs in the local network accessible for outside users.