Configure > Networking > DNS Resolver > Host Database

These setting pertain to all DNS name resolution performed by Content Gateway, including DNS Proxy.

DNS Lookup Timeout

Specifies the maximum number of seconds the proxy can wait for a lookup response from the DNS server.

Specifies how long, in seconds, the proxy will wait before making a second DNS request if there is no response to the first request. The value is stored in “proxy.config.hostdb.lookup_timeout”. The default value is 120 seconds.

Important: This setting is not used. Instead the records.config entry “proxy.config.dns.lookup_timeout” is used. The default value is 20 seconds. proxy.config.dns.lookup_timeout specifies how long the proxy will wait for the DNS response after sending the request.
Foreground Timeout

Specifies how long DNS entries remain in the host database before they are flagged as stale. This setting is used only when “proxy.config.hostdb.ttl_mode” is not zero (the default value is 0, which means use the time-to-live (ttl) value set by the DNS server. See HostDB.

For example, if this timeout is 24 hours and a client requests an entry that has been in the database for 24 hours or longer, the proxy refreshes the entry before serving it.

The default is 86400 seconds (144 minutes).

CAUTION:
Setting the foreground timeout too low might slow response time. Setting it too high risks accumulation of incorrect information.
Failed DNS Timeout

Specifies how long, in seconds, that a hostname is retained in the failed DNS lookup cache (default = 60). When the timeout expires, the hostname is removed from the cache and the next request for that hostname is sent to the DNS server.

A DNS lookup failure is considered to have occurred when:

  • There is no DNS response
  • There is a DNS response error code, including NXDOMAIN
  • There is an error parsing the DNS response code (there is a malformed response).

Zero (0) is not a legal value.