Overview

Services are defined by a communication protocol and by a port number (e.g. the HTTP service uses the TCP protocol with the port number 80). You can create groups of services that simplifies creating traffic rules.

You can also match the so-called protocol inspector with certain service types.

Solution

Example: You want to perform a protocol inspector of the HTTP protocol at port 8080

1. In the administration interface, navigate to Definitions > Services. Some standard services, such as HTTP, FTP, DNS are already predefined.
2. Click Add -> Add Service.
   
3. In the Add Service dialog, type a name of a new service — HTTP 8080.
4. Type a description.
5. Select a TCP protocol.

   Note: The other option allows protocol specification by the number in the IP packet header. Any protocol carried in IP (e.g. GRE — protocol number is 47) can be defined this way.

6. Select the HTTP protocol inspector.
   
7. Type 8080 as the Destination port. If the TCP or UDP communication protocol is used, the service is defined with its port number. In the case of standard client-server types, a server is listening for connections on a particular port (the number relates to the service), whereas clients do not know their port in advance (ports are assigned to clients during connection attempts). This means that source ports are usually not specified, while destination ports are usually known in case of standard services. Source and destination ports can be specified as:
   1. Any — all the ports available (1-65535)
   2. Equal to — a particular port (e.g.80)
   3. Greater than, Less than — all ports with a number that is either greater or less than the number defined
   4. In range — all ports that fit the defined range (including the initial and the terminal ones)
   5. List — list of the ports divided by commas (e.g. 80,8000,8080)
8. Click OK to save the settings. The custom service is shown in the Services based on the name.
9. Click Apply.
   

Testing

The HTTP protocol inspector will be automatically applied to any TCP traffic at port 8080 and passing through Kerio Control.