ZyXEL Communications zywall 50 User Manual
ZyWALL 50 Internet Security Gateway
Creating Custom Rules
10-7
10.5 Predefined Services
The Available Services list box in the Rule Config(uration) screen (see Figure 10-4) displays all predefined
services that the ZyWALL already supports. Next to the name of the service, two fields appear in brackets.
The first field indicates the IP protocol type (TCP, UDP, or ICMP). The second field indicates the IP port
number that defines the service. (Note that there may be more than one IP protocol type. For example, look at
the default configuration labeled “(DNS)”.
services that the ZyWALL already supports. Next to the name of the service, two fields appear in brackets.
The first field indicates the IP protocol type (TCP, UDP, or ICMP). The second field indicates the IP port
number that defines the service. (Note that there may be more than one IP protocol type. For example, look at
the default configuration labeled “(DNS)”.
(UDP/TCP:53)
means UDP port 53 and TCP port 53. Up to 128
entries are supported. Custom services may also be configured using the Custom Ports function discussed
later.
later.
Table 10-2 Predefined Services
SERVICE DESCRIPTION
AIM(TCP:5190)
AOL’s Internet Messenger service, used as a listening port by ICQ.
BGP(TCP:179)
Border Gateway Protocol.
BOOTP_CLIENT(UDP:68)
DHCP Client.
BOOTP_SERVER(UDP:67)
DHCP Server.
CU-SEEME(TCP/UDP:7648,
24032)
24032)
A popular videoconferencing solution from White Pines Software.
DNS(UDP/TCP:53)
Domain Name Server, a service that matches web names (e.g.
www.zyxel.com
) to IP numbers.
FINGER(TCP:79)
Finger is a UNIX or Internet related command that can be used to find
out if a user is logged on.
out if a user is logged on.
FTP(TCP:20.21)
File Transfer Program, a program to enable fast transfer of files,
including large files that may not be possible by e-mail.
including large files that may not be possible by e-mail.
H.323(TCP:1720)
Net Meeting uses this protocol.
HTTP(TCP:80)
Hyper Text Transfer Protocol - a client/server protocol for the world wide
web.
web.
HTTPS
HTTPS is a secured http session often used in e-commerce.
ICMP
ICMP service allows normal ICMP packets to go through.
ICQ(UDP:4000)
This is a popular Internet chat program.
IKE(UDP:500)
The Internet Key Exchange algorithm is used for key distribution and
management.
management.
IPSEC_TUNNEL(ESP:0)
This service is used by the IPSec ESP (Encapsulation Security Protocol)
tunneling protocol.
tunneling protocol.
IRC(TCP/UDP:6667)
This is another popular Internet chat program.