Technical Reference - ZyXEL Communications P-870HN-5xb User Manual

Use this screen to enable or disable the SIP (VoIP) ALG in the Device. To access
this screen, click NAT > ALG.
Figure 77 NAT > ALG
Each field is described in the following table.
Table 45 NAT > ALG
LABEL
Enable SIP ALG
Apply

8.7 Technical Reference

The following section contains additional technical information about the Device
features described in this chapter.
Port Forwarding: Services and Port Numbers
The most often used port numbers are shown in the following table. Please refer
to RFC 1700 for further information about port numbers. Please also refer to the
Supporting CD for more examples and details on port forwarding and NAT.
Table 46 Services and Port Numbers
SERVICES
ECHO
FTP (File Transfer Protocol)
SMTP (Simple Mail Transfer Protocol)
DNS (Domain Name System)
Finger
HTTP (Hyper Text Transfer protocol or WWW, Web)
POP3 (Post Office Protocol)
NNTP (Network News Transport Protocol)
SNMP (Simple Network Management Protocol)
P-870HN-5xb User's Guide
DESCRIPTION
Select this check box to allow SIP sessions to pass through the Device.
SIP is a signaling protocol used in VoIP (Voice over IP), the sending of
voice signals over Internet Protocol.
Click Apply to save your customized settings.
Chapter 8 Network Address Translation (NAT)
PORT NUMBER
7
21
25
53
79
80
110
119
161
157