- Kerio WinRoute Firewall Administrator's Guide

Chapter 5 Settings for Interfaces and Network Services

they are considered primary, secondary, etc.). This option should be used when

there is the need to monitor where DNS queries are forwarded to or to create a

more complex conﬁguration.

Enable cache for faster response of repeated queries

If this option is on, all responses will be stored in local DNS Forwarder cache.

Responses to repeated queries will be much faster (the same query sent by various

clients is also considered as a repeated query).

Physically, the DNS cache is kept in RAM. However, all DNS records are also saved in

the DnsCache.cfg ﬁle (see chapter 23.2). This means that records in DNS cache are

kept even after WinRoute Firewall Engine is stopped or WinRoute is disconnected.

Notes:

1. Time period for keeping DNS logs in the cache is speciﬁed individually in each

log (usually 24 hours).

2. Use of DNS also speeds up activity of the built-in proxy server (see chapter 5.5).

Clear cache

Click this button to remove all records in the DNS Forwarder’s cache (regardless of

their lifetime). This feature can be helpful e.g. for conﬁguration changes, dial-up

testing, error detection, etc.

Use custom forwarding

Use this option to enable settings for forwarding certain DNS queries to other DNS

servers.

Enable DNS forwarding

DNS forwarder allows forwarding of certain DNS requests to speciﬁc DNS servers. Re-

quest forwarding is deﬁned by rules for DNS names or subnets. If a DNS name or a sub-

net in a request matches a rule, the request is forwarded to the corresponding DNS

server. Requests matching no rule are forwarded to DNS servers in accordance with

settings in the DNS forwarding section (see above).

Note: If the simple DNS resolution is enabled (see below), the forwarding rules are ap-

plied only if the DNS Forwarder is not able to respond by using the information in the

hosts system ﬁle and/or by the DHCP lease table.

DNS forwarding can be helpful for example when we intend to use a local DNS server

for the local domain (the other DNS queries will be forwarded to the Internet directly —

this will speed up the response). DNS forwarder’s settings also play role in conﬁguration

of private networks where it is necessary to provide correct forwarding of requests for

names in domains of remote subnets (for details, check chapter

21).

Use the Deﬁne button to open the dialog for deﬁnition of DNS forwarding rules.