----- Original message -----
> Hi list,
>
> With keep_hostname(yes), when the syslog-ng box receives a message which
> does not have a host field, you end up with the last hop IP as the
> hostname. Is there already a way to tell sysng to use_dns() when this
> situation is encountered?

it is exactly the use-dns option that controls this.

>
> I'd like to continue using keep_hostname(yes) for all log messages which
> do have a hostname included, but in the instance that hostname is not
> included, have syslog-ng do a reverse dns lookup in order to resolve
> hostname.
>

this is the behaviour for use-dns(yes)