There are several options of the syslog-ng server running on SSB that can be configured. These include:
For details on general syslog-ng settings — see General syslog-ng settings.
For details on timestamping-related options — see Timestamping configuration on SSB.
For details on certificate management for receiving and sending log messages in TLS-encrypted channels —, see Setting the certificates used in TLS-encrypted log transport.
For details on managing domain name resolution for log messages — see Using name resolution on SSB.
To configure the general options of the syslog-ng server running on SSB, navigate to Log > Options. The following options are available (note that options related to name resolution are discussed in Using name resolution on SSB):
Figure 124: Log > Options — Configuring syslog-ng options
Message size: Specifies the maximum length of incoming log messages in bytes. This option corresponds to the log-msg-size() parameter of syslog-ng. The maximum value of this parameter is 1000000 (1 MB).
To be able to edit the Message size, you must have write/perform permission for the Basic Settings > System page. For details on how to assign user rights, see Managing user rights and usergroups.
Wait time between polls: The time to wait in milliseconds before checking if new messages have arrived to a source. This option corresponds to the time-sleep() parameter of syslog-ng.
Idle time before destination is closed: The time to wait in seconds before an idle destination file is closed. This option corresponds to the time-reap() parameter of syslog-ng.
Cipher: Select the cipher method used to encrypt the logstore. The following cipher methods are available: aes-128-cbc, aes-128-cfb, aes-128-cfb1, aes-128-cfb8, aes-128-ecb, aes-128-ofb, aes-192-cbc, aes-192-cfb, aes-192-cfb1, aes-192-cfb8, aes-192-ecb, aes-192-ofb, aes-256-cbc, aes-256-cfb, aes-256-cfb1, aes-256-cfb8, aes-256-ecb, aes-256-ofb, aes128, aes192, aes256, bf, bf-cbc, bf-cfb, bf-ecb, bf-ofb, cast5-cbc, cast5-cfb, des-cbc, des-cfb, des-cfb1, des-cfb8, des-ecb, des-ede, des-ede-cbc, des-ede-cfb, des-ede-ofb, des-ede3, des-ede3-cbc, des-ede3-cfb, des-ede3-ofb, des-ofb, desx-cbc, rc2-40-cbc, rc2-64-cbc, rc2-cbc, rc2-cfb, rc2-ecb, rc2-ofb, rc4, and rc4-40.
By default, SSB uses the aes-256-cbc method.
Digest: Select the digest method to use. The following digest methods are available: MD4, MD5, SHA-1, RIPEMD-160, SHA-224, SHA-256, SHA-384, and SHA-512.
By default, SSB uses the SHA-256 method.
The size of the digest hash must be equal to or larger than the key size of the cipher method. For example, to use the aes-256-cbc cipher method, the digest method must be at least SHA-256.
To configure the timestamping options of SSB, navigate to Log > Options. The following options are available:
Timestamp server: Select the timestamping server to use for signing encrypted logspaces. To use the built-in timestamp server of SSB, select Local.
To use an external timestamping server, select Remote and enter the address of the server into the Server URL field in the following format:
http://<IP address>:<port number>/
Note that currently only plain HTTP services are supported, password-protected and HTTPS services are not supported.
SSB currently supports only timestamping servers that use the Internet X.509 Public Key Infrastructure Time-Stamp Protocol (TSP) described in RFC 3161.
Timestamp policy OID: If the Timestamping Server has timestamping policies configured, enter the OID of the policy to use into the Timestamping policy field. SSB will include this ID in the timestamping requests sent to the TSA.
The timestamp requests are handled by a separate process in syslog-ng, message processing is not affected if the timestamping server is slow or cannot be accessed.
SSB can resolve the hostnames of the clients and include them in the log messages. However, the performance of SSB can be severely degraded if the domain name server is unaccessible or slow. Therefore, SSB automatically caches the results of name resolution. If you experience performance problems under high load, it is recommended to disable name resolution. If you must use name resolution, consider the following:
If the IP addresses of the clients change only rarely, set the expiry of the DNS cache to a large value. By default, SSB caches successful DNS lookups for an hour, and failed lookups for one minute. These parameters can be adjusted under Log > Options > Options > DNS Cache expiry and Failed DNS cache expiry.
Figure 125: Log > Options > Options > DNS Cache expiry — Configuring DNS options
Resolve the hostnames locally. Resolving hostnames locally enables you to display hostnames in the log files for frequently used hosts, without having to rely on a DNS server. The known IP address – hostname pairs are stored locally in a file. In the log messages, syslog-ng will replace the IP addresses of known hosts with their hostnames. To configure local name resolution, select Log > Options > Name resolving, and enter the IP Address - hostname pairs in (for example 192.168.1.1 myhost.example.com) into the Persistent hostname list field. Then navigate to Log > Sources, and set the Use DNS option of your sources to Only from persistent configuration.
Figure 126: Log > Options > Name resolving — Configuring persistent name resolution