SILCD_CONF(5)

NAME
silcd.conf - format of configuration file for silcd

CONFIGURATION FILE
Silcd reads its configuration from /etc/silc/silcd.conf (or the file specified with -f). The file contains sections, subsections and key-value pairs. Each section or subsection is bound with a starting { and ending }. Keys and values are of the format ’KEY=VALUE;’. All statements as well as sections must be terminated with a ’;’.

Mandatory section in configuration file is ServerInfo. Other sections are optional but recommended. If General section is defined it must be defined before the ConnectionParams section. On the other hand, the ConnectionParams section must be defined before Client, ServerConnection and/or RouterConnection sections. Other sections can be in a free order in the configuration file.

SECTION: General

General section contains global settings for the silcd.

dynamic_server
    Dynamic router connections. If this is set for normal SILC server the connection to primary router is not created untill it is actually needed. Giving for example /WHOIS foobar@silcnet.org would then create connection to the primary router to resolve user foobar. On the other hand giving /WHOIS foobar would try to search the user foobar locally, without creating the connection. Note that giving /JOIN foobar will also created the connection as current SILC Server version supports only global channels (all JOINs require connection to router, if one is configured).

prefer_passphrase_auth
    If both public key and passphrase authentication are set for a connection, public key authentication is by default preferred. Setting this value to true causes silcd to prefer passphrase authentication in these cases.

require_reverse_lookup
    Set this value to true if all connecting hosts must have a fully qualified domain name (FQDN). If set to true, a host without FQDN is not allowed to connect to server.

connections_max
    Maximum number of incoming connections to this server. Any further connections are refused.

connections_max_per_host
    Maximum number of incoming connections from any single host. This setting can be overridden on a connection-specific basis with ConnectionParams.

version_protocol
    Defines the minimum required version of protocol to allow connecting to server. A client or server using this version of protocol or newer is allowed to connect, one using anything older will be rejected. Leaving unset allows all versions to connect. This can be overridden with ConnectionParams.

version_software
    Defines the minimum required version of software to allow connecting to server. A client or server that is of this version or newer is allowed to connect, one using anything older will be rejected. Leaving unset allows all versions to connect. This can be overridden with ConnectionParams.

version_software_vendor
    Defines the allowed software vendor string that is required to connect. Usually this is either a build number or special client tag. Using this requirement is not encouraged unless the server is in very limited use. Leaving unset allows all versions regardless of their vendor to connect. Can be overridden with ConnectionParams.

key_exchange_rekey
    Defines the interval, in seconds, how often the session key will be regenerated. This setting only applies to the connection initiator, as rekey is always performed by the initiating party. Setting has effect only when the server acts as an initiator, and can be overridden with ConnectionParams.

key_exchange_pfs
    Boolean value to determine, whether key-exchange is performed with Perfect Forward Secrecy (PFS) or without. If set to true, the rekey process will be somewhat slower, but more secure since the key is entirely regenerated. Can be overridden with ConnectionParams.

key_exchange_timeout
    Key exchange timeout in seconds. If the key exchange is not completed within this time, the remote connection will be closed.

conn_auth_timeout
    Connection authentication timeout in seconds. If the connection authentication is not completed within this time, the remote connection will be closed.

channel_rekey_secs
    Seconds, how often channel key will be regenerated. Note that channel key is regenerated each time someone joins or leaves the channel. This is the maximum time any channel can have the same key.

detach_disabled
    Boolean value controlling, whether clients are denied the use of DETACH command. Default value is false (DETACH is allowed).

detach_timeout
    Time in seconds how long detached sessions will be available. By default, detached sessions do not expire and as such, are persistent as long as the server is running. If DETACH command is allowed, this value should be set as well.

qos
    Boolean value controlling, whether Quality of Service settings are enabled. Default setting is false. NOTE: If you enable QoS in general section, it applies to every connection the server has, including server connections. This setting can be overridden with ConnectionParams and in case of server connections, it SHOULD BE overridden (server connections should not use QoS).

qos_rate_limit
    Limits read operations per second to given amount. Do note that one read operation may read several SILC packets, so this setting does not automatically correspond to amount of messages transmitted or accepted.

qos_bytes_limit
    Limits incoming SILC data to the specified number of bytes per second.

qos_limit_sec
    This value defines the timeout, in seconds, for the delay of received data in case it was left in a QoS queue.

qos_limit_usec
    This value defines the timeout, in microseconds, for the delay of received data for received data in case it was left in a QoS queue.

SECTION: ServerInfo

ServerInfo contains values for bound interfaces and administrative info.

hostname
    Server’s name (FQDN).

ServerType
    This is a descriptive text field, usually telling what the server and its purpose are.

Location
    Descriptive field of server’s geographic location.

Admin
    Administrator’s full name.

AdminEmail
    Administrator’s email address.

User
    The name of the user account silcd will be running on. This must be an existing user. Silcd needs to executed as root; after binding the port it will drop root privileges and use the account given here.

Group
    The name of the group silcd will be running on. This must be an existing group. Silcd needs to be executed as root; after binding the port it will drop root privileges and use the group given here.

PublicKey
    Full path to server’s public key file.

PrivateKey
    Full path to server’s private key file.

MotdFile
    Full path to MOTD (Message Of The Day) file, a text file that will be displayed to each client upon connection.

PidFile
    Full path to file where silcd will write its PID.

SUBSECTION: Primary

This is the primary listener info. Each server can have no more than one Primary section.

ip
    Specifies the address silcd is listening on.

port
    Specifies the port silcd is listening on.

public_ip
    Optional field. If your server is behind NAT this IP would be the public IP address. The ’ip’ field would include the internal IP address. With this option it is possible to run silcd behind NAT device.

SUBSECTION: Secondary

This is a secondary listener info. A server may have any amount of Secondary listener settings. These are needed only if silcd needs to listen on several interfaces. Secondary subsections have the same information that Primary does.

SECTION: Logging

This section is used to set up various log files; their paths, maximum sizes and individual logging options.

There are four defined logging channels. The log channels have an importance value, and more important channels are always redirected to the less important ones. Setting a valid logging file for Info will ensure logging for all channels, whereas a setting for Errors would only ensure logging for Errors and Fatals.

Timestamp
    A boolean value that dictates whether log lines will have timestamps prefixed. In general, this is a good idea. You might want to disable this if you are running silcd under some special logging daemon, such as daemontools.

QuickLogs
    A boolean value that determines how often log files are updated. Setting this to true makes silcd log in real-time. Setting this to false makes silcd write to logs every FlushDelay seconds. Real-time logging causes a bit more CPU and HDD usage but reduces memory consumption.

FlushDelay
    Time in seconds, how often logs are flushed to logfiles. This setting has effect only if QuickLogs is disabled.

SUBSECTION: Info

SUBSECTION: Warnings

SUBSECTION: Errors

SUBSECTION: Fatals
Each of these subsections has the same attributes, File and Size. Different levels of problems are logged to their respective channels (Info, Warnings, Errors, Fatals), depending on their need of attention.

File
    Full path to log file.

Size
    Limit the size the log file is allowed to grow to. Any further messages to this file cause the oldest lines to be removed in order to keep the file size within given limit.

SECTION: ConnectionParams

This section defines connection parameters. Each connection may have its own set of ConnectionParams but having one is in no way mandatory. If no separate parameters have been assigned, the defaults and the ones from General section will be used. A silcd configuration may have any number of ConnectionParams sections.

name
    This is a unique name that separates this particular ConnectionParams section from all the others. It is also the name with which settings are referred to a given set of parameters. This field is mandatory.

connections_max
    Limits how many concurrent connections are allowed. Any further connections are simply refused. Note that this setting can not override the figure given in General section.

connections_max_per_host
    Maximum number of connections allowed from any single host. If this parameter is set for a block controlling server connections, it is highly suggested to use a value of one (1).

version_protocol
    Exactly the same as in General section.

version_software
    Exactly the same as in General section.

version_software_vendor
    Exactly the same as in General section.

keepalive_secs
    How often (seconds) to send HEARTBEAT packets to connected clients.

reconnect_count
    When connection is lost, how many times a reconnection is tried.

reconnect_interval
    How often, in seconds, a reconnection is attempted.

reconnect_interval_max
    Reconnection time is lengthened each time an unsuccessful attempt occurs. This value defines the maximum interval to which the delay may be prolonged.

reconnect_keep_trying
    Boolean value controlling whether server eventually gives up trying to reconnect. If set to false, server will give up once reconnect_count is reached or, even at maximum interval no connection is established.

key_exchange_rekey
    Exactly the same as in General section.

key_exchange_pfs
    Exactly the same as in General section.

anonymous
    This boolean setting has meaning only to client connections. If set to true, client connections using this ConnectionParams block will have their username and host scrambled. The client will also have an anonymous mode set to it.

qos
    Exactly the same as in General section NOTE: For server connection this should be set to false value.

qos_rate_limit
    Exactly the same as in General section.

qos_bytes_limit
    Exactly the same as in General section.

qos_limit_sec
    Exactly the same as in General section.

qos_limit_usec
    Exactly the same as in General section.

SECTION: Client

This section defines how incoming client connections are handled. There can be several Client sections, each with their own requirements. A silcd admin could for example require that connections from certain IP-address space must supply a connection password.

Host
    An address or wildcarded set of addresses, either in numeric IP-address fashion or as hostnames. For example "10.1.*" or "*.mydomain.domain.org".

Passphrase
    The required passphrase to allow client connection.

PublicKey
    The path to a file containing the client’s public key. There can be any number of PublicKey statements in one Client section. Matching any of them will do.

Params
    Name of client connection parameters.

SECTION: ServerConnection

This section defines a configured server connection. A regular SILC server does not need one at all. If this block exists, it means that the server is a SILC router. There must be one ServerConnection for each SILC server that connects to this router.

Host
    Either an FQDN or strict IP-address of the connecting server.

Passphrase
    If server connection requires passphrase authentication, set it here.

PublicKey
    This is a path to connecting server’s public key. If server connection requires public key authentication, set this value. If both Passphrase and PublicKey are set, then either of them will be accepted.

Params
    Connection parameters.

Backup
    A boolean value controlling whether this server acts as a backup. Set to false for normal servers. If set to true, this server is a backup router.

SECTION: RouterConnection
This section covers router connections. Stand-alone servers won’t have this section, and regular servers should only have one.

Router servers need one RouterConnection for each other router they have been configured to connect to. First configured section is the primary route.

Port
    If Initiator is set tro true, this setting defines the remote port in which to connect. if Initiator is set to false, then this defines the local (listening) port.

Passphrase
    If connecting server requires a passphrase authentication, it is set here.

PublicKey
    If connecting to server requires public key authentication, the path to server’s public key file is set here.

Params
    Connection parameters.

Initiator
    A boolean setting that defines whether this server is the connecting party.

BackupHost
    If the configured connection is a backup connection, set this to the address of the main router that will be replaced. For normal router connection leave this option out.

BackupPort
    If the configured connection is a backup connection, set this to the remote port which to connect to. For normal router connection, leave this option out.

BackupLocal
    A boolean value. If this setting is true, then the backup router is in the same cell. If the backup router is in another cell, set this to false. Needless to say, for normal router connection, leave this option out.

SECTION: Admin

This section defines configured administration connections.

Host
    Either FQDN or a strict IP-address to the origin of connection. This field is optional.

User
    Username that the connecting client announces. This field is optional.

Nick
    Nickname that the connecting client announces. This field is optional.

Passphrase
    Passphrase required to obtain server operator privileges.

PublicKey
    Path to administrator’s public key file. If both Passphrase and PublicKey are defined, either one can be used.

SECTION: Deny
This section defines denied incoming connections. They apply equally to both client and server connections, so make sure you know what you add here. Each Deny section covers one instance of denied connection(s). There may be any number of Deny sections.

Host
    Address or wildcarded addresses of denied connections. NOTE! This field is not mandatory, but highly recommended. If you don’t specify Host at all, or give it a value of "*", you have a silcd that denies every single incoming connection.

Reason
    A string giving the reason as to why the connecting party is not allowed to connect. Unlike Host, this field IS mandatory.

FILES
silcd.conf

SEE ALSO
silcd(8)

AUTHOR
SILC is designed and written by Pekka Riikonen <priikone@iki.fi> and rest of the SILC Project.

Configuration file format and parser is by Giovanni Giacobbi <giovanni@giacobbi.net>.

This manpage was written by Mika ’Bostik’ Boström <bostik@lut.fi>

See CREDITS for full list of contributors.