Windows Server DNS Server can't forward to pfSense

[netblues]

@Hekmil server fail means can't get response from upstream.
This is expected

Enable dns resolver forwading to your dns gateway and it will also work

[Hekmil]

@netblues DNS Resolver Forwarding mode is enabled

[netblues]

@Hekmil and what do you have in system\general\dns ?

[Hekmil]

@netblues My NAT Gateway as DNS Server

The 2 boxes are checked. I've try to uncheck them to randomly test something but as expected nothing different

[netblues]

@Hekmil dig @yournasip cnn.com
what happens?

[Hekmil]

@netblues With NAT ip address everything is fine, just switching to LAN ip won't make it

; <<>> DiG 9.14.12 <<>> @192.168.101.2 cnn.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 63875
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 4, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; MBZ: 0x0005, udp: 4096
;; QUESTION SECTION:
;cnn.com.			IN	A

;; ANSWER SECTION:
cnn.com.		5	IN	A	151.101.129.67
cnn.com.		5	IN	A	151.101.65.67
cnn.com.		5	IN	A	151.101.193.67
cnn.com.		5	IN	A	151.101.1.67

;; AUTHORITY SECTION:
cnn.com.		5	IN	NS	ns-1086.awsdns-07.org.
cnn.com.		5	IN	NS	ns-1630.awsdns-11.co.uk.
cnn.com.		5	IN	NS	ns-47.awsdns-05.com.
cnn.com.		5	IN	NS	ns-576.awsdns-08.net.

;; Query time: 11 msec
;; SERVER: 192.168.101.2#53(192.168.101.2)
;; WHEN: Thu Jul 23 14:42:25 CEST 2020
;; MSG SIZE  rcvd: 236

[netblues]

@Hekmil But you get server failed, not no servers can be reached, right?

ping -S 172.16.1.2 192.168.101.2 works?

[Hekmil]

@netblues Yes I get Server can't find cnn.com : SERVFAIL

No it doesn't ping, that might be a route issue no ?

[netblues]

@Hekmil Do you have outbound nat enabled on your wan interface?

[Hekmil]

@netblues Oh my god...

The Outbound NAT configuration was set to automatic (which should have been enought right ?). So I tried to switch to manual and create a map ANY/ANY on WAN and everything works !

[netblues]

@Hekmil Your configuration is not exactly typical and "automatic" things sometimes fail.
From a technical point of view, pf being a router, you shouldn't need nat to reach an rfc1918 address.
I suspect that packets reach your nas gateway, but never return.

Most probably your nas gateway needs a route back for 172.16.1.0/24 pointing to your pfwan interface ip.
Natting, (double) just makes the call originate from the wan interface.
And connected networks don't need routes.

[Hekmil]

@netblues Yes I also think it reachs the nat gateway considering the logs but never returning.

I don't know how and where to set a route for my nat gateway though

[netblues]

@Hekmil Maybe you can't. You have to figure this out
In the mean time, stay with double nat.
For simple internet connectivity and dns resolution it won't make any difference.

[Hekmil]

@netblues I'm pretty I can't yes, so far the only thing I could change about the NAT configuration was the network IP and Gateway.

Yeah it'll do juste fine. Thanks anyway !