When configured as a DNS proxy, the firewall is an intermediary between
DNS clients and servers; it acts as a DNS server itself by resolving
queries from its DNS proxy cache. If it doesn’t find the domain
name in its DNS proxy cache, the firewall searches for a match to
the domain name among the entries in the specific DNS proxy object
(on the interface on which the DNS query arrived). The firewall
forwards the query to the appropriate DNS server based on the match results.
If no match is found, the firewall uses default DNS servers.
A DNS proxy object is where you configure the settings that determine
how the firewall functions as a DNS proxy. You can assign a DNS
proxy object to a single virtual system or it can be shared among
all virtual systems.
If the DNS proxy object is for a virtual system, you
can specify a DNS Server Profile, which
specifies the primary and secondary DNS server addresses, along
with other information. The DNS server profile simplifies configuration.
If the DNS proxy object is shared, you must specify at least
the primary address of a DNS server.
configuring multiple tenants (ISP subscribers) with DNS services,
each tenant should have its own DNS proxy defined, which keeps the
tenant’s DNS service separate from other tenants’ services.
In the proxy object, you specify the interfaces for which the
firewall is acting as DNS proxy. The DNS proxy for the interface
does not use the service route; responses to the DNS requests are
always sent to the interface assigned to the virtual router where
the DNS request arrived.
When you Configure a DNS Proxy Object, you can supply
the DNS proxy with static FQDN-to-address mappings. You can also
create DNS proxy rules that control to which DNS server the domain
name queries (that match the proxy rules) are directed. You can
configure a maximum of 256 DNS proxy objects on a firewall. You
Cache EDNS Responses
) if this DNS proxy object
is assigned to
. Furthermore, if this DNS proxy
DNS proxy rules
rules also need to have cache enabled (
Turn on caching
of domains resolved by this mapping
When the firewall receives an FQDN query (and the domain name
is not in the DNS proxy cache), the firewall compares the domain
name from the FQDN query to the domain names in DNS Proxy rules
of the DNS Proxy object. If you specify multiple domain names in
a single DNS Proxy rule, a query that matches any one of the domain
names in the rule means the query matches the rule. DNS Proxy Rule and FQDN Matching describes
how the firewall determines whether an FQDN matches a domain name
in a DNS proxy rule. A DNS query that matches a rule is sent to
the primary DNS server configured for the proxy object to be resolved.