# Service elements

Service elements are used in Access rules to match traffic and to set parameters for handling the traffic.

There are predefined system Service elements for official (IANA-reserved) and well-known protocols and services (such as DNS, FTP, and HTTP). You can also create your own custom Service elements to specify a port that is not predefined or to define custom options for handling some types of traffic.

Table 1. Types of Services
Element Type | Explanation
--- | ---
Group | Groups of services containing the Service elements that together fulfill a certain role (for example, the services that allow IPsec VPN connections).
ICMP | Identifies the message by the ICMP Type and Code fields.
IP-proto | Identifies the protocol by the IP address header Protocol field.
SUN-RPC | Identifies the Sun remote procedure call (RPC) service by the program identifier.
TCP | Identifies the service by the TCP header Source Port or Destination Port fields.
UDP | Identifies the service by the UDP header Source Port or Destination Port fields.
With Protocol | Default Services containing Protocols that have default parameters set to typically used values.
With Proxy | Default Services containing SSM Proxy Protocol Agents.