This option specifies the time to wait for the DNS server to respond to lookup queries. The default is 8 seconds. You may change this value if you are accessing a slow DNS server, or requests go through a slow network link.
This timeout value should only be increased if you are trying to resolve addresses via NetBOIS (Machine names of computers running Windows). Sometimes NetBOIS names can take up to 20 seconds to resolve via a unicast lookup request.
If your DNS server is local and you are only resolving internal addresses, you can safely reduce your timeout value down to 3 seconds.
If you increase the timeout value too much, you may find that the messages are being queued up waiting for the resolution to finish. In this case, when the queue reaches 1000 entries, messages will be dropped. The message buffer free space can be seen from the main syslog screen.