6.1 Service Parameter Settings
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## 6.1 Service Parameter Settings

The service list (see figure 6.1 Services) includes the following information:

- Service — includes protocol name and an icon informing whether the service is running or stopped.

- Status (running/stopped) — this item shows whether the service is running or stopped.

- Startup (Manual/Automatic) — information whether Kerio MailServer is started automatically or it must be run manually upon its restart.

- IP addresses — this item shows all IP addresses and ports used for traffic by the particular Kerio MailServer's service.

- Limit Access — Kerio MailServer allows narrowing access rights to a certain group of IP addresses which will be allowed to use the particular service (usually, unsecured services are accessible from the local network only).

The parameters of a selected service can be changed. To do this, use the Edit button. The button opens the Service dialog (see figure 6.2 Service Parameters). The dialog consists of the following tabs:

### Features

This tab allows setting of startup type and of a TCP port for traffic.

Figure 6.2. Service Parameters

Name

  Type of service.

Startup

  Kerio MailServer allows two startup modes:

  - Automatically — the service will be run automatically upon Kerio MailServer's startup.

  - Manually — when the server is started, the service is stopped and it must be run by the administrator if desirable.

Listen IP Addresses and Ports

  By default, Kerio MailServer listens at all default ports at all IP addresses of the its host. The Ports dialog enables to assign particular IP address to the port where the service is running.

  Assignment of an IP address to a standard port of a service running in Kerio MailServer may be helpful in the case that Kerio MailServer and another application using the same services (e.g. another LDAP server, webserver or mail server) are installed at the same host. In such a case, it is possible to reserve only one IP address for each service of Kerio MailServer so that port collisions are avoided.

  This means that two different web servers may use port 80 at two different IP addresses.[2]

  ### Warning

  Assignment of IP addresses to ports is not recommended if IP addresses are reserved dynamically, e.g. using DHCP.

  Click Add to bind the IP address to the port.

  Figure 6.3. Ports

  Most services use standard ports and it is not recommended to change them unless necessary (e.g. in case of conflict with another application of the same type). Click Default to restore the default settings.

### Access

The Access tab allows setting limits for access to the particular service. The following parameters can be set:

Figure 6.4. Limiting access to service

Allow access only from...

  Allows access to a selected service to be limited to certain IP addresses only (defined in the selected group). The IP address group can be defined in the Configuration/Definitions/IP Address Groups section or directly in this dialog window by pressing the Edit button.

  Detailed access policy for the SMTP service can be set in the Configuration → SMTP server section.

Allow anonymous access

  This option relates only to the NNTP(S) service, therefore it is not contained in other dialog windows of other services. This option allows unauthenticated access to the NNTP server. This means that everyone can register to a mailing list with anonymous access.

Max. number of concurrent connections

  This option limits the number of concurrent connections to the selected service. Too many concurrent connections may cause the server overload which can subsequently lead to its failure. This is the principal of so called DoS (Denial of Service) attack. Setting the limit for the number of connections therefore helps to prevent the DoS attacks against your server.

  ### Warning

  When you plan to limit the number of connections, consider the number of server users.

[2] Indeed, it is necessary to reserve an IP address for the same service in another application, that is not used by Kerio MailServer.

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Chapter 6 Services | Contents | 6.2 Important Notes