# How relaying log messages works

Depending on your exact needs about relaying log messages, there are many scenarios and AxoSyslog options that influence how the log message will look like on the logserver. Some of the most common cases are summarized in the following example:

Consider the following example: _client-host > relay > server_, where the IP address of `client-host` is `192.168.1.2`. The `client-host` device sends a syslog message to `relay`. Depending on the settings of `relay`, the following can happen.

  * By default, the `keep-hostname()` option is disabled, so `relay` writes the IP address of the sender host (in this case, `192.168.1.2`) to the HOST field of the syslog message, discarding any IP address or hostname that was originally in the message.

  * If the `keep-hostname()` option is enabled on `relay`, but name resolution is disabled (the `use-dns()` option is set to `no`), `relay` uses the HOST field of the message as-is, which is probably `192.168.1.2`.

  * To resolve the `192.168.1.2` IP address to a hostname on `relay` using a DNS server, use the `keep-hostname(no)` and `use-dns(yes)` options. If the DNS server is properly configured and reverse DNS lookup is available for the `192.168.1.2` address, AxoSyslog will rewrite the HOST field of the log message to `client-host`.

Note It is also possible to resolve IP addresses locally, without relying on the DNS server. For details on local name resolution, see [Resolving hostnames locally](../../../docs/axosyslog-core/chapter-examples/examples-dns/example-local-dns/index.md). 

  * The above points apply to the AxoSyslog server (`server`) as well, so if `relay` is configured properly, use the `keep-hostname(yes)` option on `server` to retain the proper HOST field. Setting `keep-hostname(no)` on `server` would result in AxoSyslog rewriting the HOST field to the address of the host that sent the message to `server`, which is `relay` in this case.

  * If you cannot or do not want to resolve the `192.168.1.2` IP address on `relay`, but want to store your log messages on `server` using the IP address of the original host (that is, `client-host`), you can enable the `spoof-source()` option on `relay`. However, `spoof-source()` works only under the following conditions:

    * The `syslog-ng` binary has been compiled with the `--enable-spoof-source` option.
    * The log messages are sent using the highly unreliable UDP transport protocol. (Extremely unrecommended.)



Last modified December 11, 2023: [Rename content/chapter-quickstart to content/quickstart (ba5e73a)](<https://github.com/axoflow/axosyslog-core-docs/commit/ba5e73adf87011c3d8beb6fe017b02431dbcb5fd>)