Forward DNS requests

[panos]

Hi,

We are looking for a way to forward All dns requests to internal DNS ip.

Either client changes its ip address to public dns addresses it should be forwarded to internal.

Can we do that ?

We don't want to write a deny rule for public Dns requests.

We don't want to enforce client's dns.

[VinceM]

Hi,

If you configure a dns proxy it should work.

The only limit is dns proxy can only be apply to suer traffic not palo management interface.

V.

[panos]

That did not work.When you use dns proxy can you override client Dns config ?

[VinceM]

Hi,

Not changing the client DNS but proxify it.

Client send request for xxx.mydomain.com to 8.8.8.8 dns server

Arrive on the palo, palo proxy the request and forward to 172.16.10.10

this is what you want ?

V.

[panos]

we tried that but didn't work

ex. you have Lan and Wan interface

in dns proxy how should we configure to do that ?

adding interface and type dns on left is enough ?

[mr.linus]

why not just add a destination NAT?

source: trust

destination: untrust

service: DNS

=> destination NAT to your DNS server

now all DNS requests to an external server are routed to your DNS server.

Just keep a look out for asymmetric routing.

[VinceM]

Hi,

Come back to the office, take a palo and test. You're right, for dns proxy working, dns client have to be configured on palo's interface ip.

In my mind it should act as transparent dns proxy .... but no.

take in consideration the LinusRaes solution, do your redirection through nat rule.

V.

[panos]

This is not working for any ip.you cannot dest. NAT any ip to 1 ip

[ericgearhart]

You know honestly it's not a "DNS Proxy" at all... I thought it would be transparent when I saw the name "DNS Proxy" too. They really ought to just name it flat out "Caching Only DNS Server," because that's essentially what it it (with some static entries permitted in order to do DNS doctoring)    

[mr.linus]

This is not working for any ip.you cannot dest. NAT any ip to 1 ip

ahhh, that's right, I forgot. If i recall correctly Juniper can do this 😉

[panos]

I tested but it did not work

there is ony 1 nat rule and 1 security rule in test lab

[VinceM · Accepted solution]

It is necessary to face the facts, it should be not possible, otherwise you have to install a transparent proxy.

V.

[panos]

sometimes there are solutions that we can't remember

Thanks for answers all.

[mikand]

Doesnt PANOS 5.0 contain a dns-proxy where you can rewrite dns-queries passing through so they are forced to a dns-server of your choice?

[craymond]

According to the Docs:

For all DNS queries that are directed to an interface IP address, the firewall supports the selective directing of queries to different DNS servers based on full or partial domain names. TCP or UDP DNS queries are sent through the configured interface. UDP queries fail over to TCP when a DNS query answer is too long for a single UDP packet.

If the domain name is not found in the DNS proxy cache, the domain name is searched for a match based on configuration of the entries in the specific DNS proxy object (on the interface on which the DNS query arrived) and forwarded to a name server based on the match results. If no match is found, the default name servers are used. Static entries and caching are also supported.

It would be interesting to try.