Kerio Tech Firewall6 User Manual
Page 107
8.1 DNS Forwarder
107
names. When any DNS query is received, this file will be checked first to find out
whether the desired name or IP address is included. If not, the query is forwarded
to a DNS server.
If this function is on, DNS Forwarder follows the same rule. Use the Edit button to
open a special editor where the hosts file can be edited within the Administration
Console even if this console is connected to WinRoute remotely (from another
host).
Figure 8.4
Editor of the Hosts system file
•
DHCP lease table— if the hosts within local network are configured by the DHCP
server in WinRoute (see chapter
), the DHCP server knows what IP address was
defined for each host. After starting the system, the host sends a request for IP
address definition including the name of the host.
DNS Forwarder can access DHCP lease tables and find out which IP address has
been assigned to the host name. If asked to inform about the local name of the
host, DNS Forwarder will always respond with the current IP address.
Note: If both options are disabled, the DNS Forwarder forwards all queries to other DNS
servers.
Local DNS domain
In the When resolving name from the ’hosts’ file or lease table combine it with DNS domain
below entry, specify name of the local DNS domain.
If a host or a network device sends a request for an IP address, it uses the name only
(it has not found out the domain yet). Therefore, only host names without domain are
saved in the table of addresses leased by DHCP server . DNS Forwarder needs to know the
name of the local domain to answer queries on fully qualified local DNS names (names
including the domain).
Note: If the local domain is specified in DNS Forwarder, local names with or without the
domain can be recorded in the hosts system file.
The problem can be better understood through the following example.