Windows Server DNS Server can't forward to pfSense

netblues

@Hekmil not much left to do.
can you ping pfsense lan from windows server?

Hekmil

@netblues Yeah that's why i'm asking here, because I'm out of option

Yes all my machines can ping together. But only pfSense can ping outside the NAT (for example 8.8.8.8).

Here is a tracert command to 8.8.8.8 which timeout after reaching pfSense LAN interface. The firewall log :

netblues

And you cant nslookup from everywhere else with pfsense lan ip but you can from pfsense cli using lan ip.
Anything on floating rules?

Hekmil

@netblues Wait I was only trying to do nslookup cnn.com on the cli not using lan IP. If I do that it doesn't work of course sorry. It's like the resolving DNS service was not enabled for all interfaces except it is.

Floating rules are empty.

netblues

@Hekmil please post services resolver settings.
Have you tried restarting resolver service?

Hekmil

@netblues Here are my setting of my resolver :

192.168.101.2 = NAT Gateway

Yes the service and even the machine has been restarted trying fixing the issue

netblues

@Hekmil you dont really need any dns servers if pf can reach the internet..
However this is irrelevant.
Dns resolver should be listening on lan anyway.
Do restart the srrvice and look at status system logs resolver logs for anything strange.

Hekmil

@netblues True that

Nothing really usefull from the logs :

netblues

@Hekmil output of sockstat -l please

Hekmil

@netblues

USER     COMMAND    PID   FD PROTO  LOCAL ADDRESS         FOREIGN ADDRESS
root     sockstat   96752 13 stream /var/run/php-fpm.socket
unbound  unbound    52451 3  udp6   *:53                  *:*
unbound  unbound    52451 4  tcp6   *:53                  *:*
unbound  unbound    52451 5  udp4   *:53                  *:*
unbound  unbound    52451 6  tcp4   *:53                  *:*
unbound  unbound    52451 7  tcp4   127.0.0.1:953         *:*
unbound  unbound    52451 12 stream /var/run/php-fpm.socket
unbound  unbound    52451 13 stream /var/run/php-fpm.socket
unbound  unbound    52451 14 udp4   *:52518               *:*
root     syslogd    45622 6  dgram  /var/dhcpd/var/run/log
root     syslogd    45622 7  udp6   *:514                 *:*
root     syslogd    45622 8  udp4   *:514                 *:*
root     syslogd    45622 9  dgram  /var/run/log
root     syslogd    45622 10 dgram  /var/run/logpriv
root     syslogd    45622 12 stream /var/run/php-fpm.socket
root     syslogd    45622 13 stream /var/run/php-fpm.socket
root     php-fpm    17426 3  dgram  (not connected)
root     php-fpm    17426 4  udp4   *:*                   *:*
root     php-fpm    17426 5  udp6   *:*                   *:*
root     php-fpm    17426 13 stream /var/run/php-fpm.socket
root     ntpd       37361 20 udp6   fe80::20c:29ff:fe82:c819%em0:123 *:*
root     ntpd       37361 21 udp4   192.168.101.40:123    *:*
root     ntpd       37361 22 udp6   fe80::20c:29ff:fe82:c823%em1:123 *:*
root     ntpd       37361 23 udp4   172.16.1.2:123        *:*
root     ntpd       37361 24 udp6   fe80::20c:29ff:fe82:c82d%em2:123 *:*
root     ntpd       37361 25 udp4   172.16.101.2:123      *:*
root     ntpd       37361 26 udp6   fe80::20c:29ff:fe82:c837%em3:123 *:*
root     ntpd       37361 27 udp4   172.16.4.2:123        *:*
root     ntpd       37361 28 udp6   fe80::20c:29ff:fe82:c841%em4:123 *:*
root     ntpd       37361 29 udp4   172.16.200.2:123      *:*
root     ntpd       37361 30 udp6   ::1:123               *:*
root     ntpd       37361 31 udp4   127.0.0.1:123         *:*
root     login      80435 3  dgram  (not connected)
root     charon     22942 5  dgram  (not connected)
root     charon     22942 8  stream /var/run/charon.wlst
root     charon     22942 11 udp6   *:500                 *:*
root     charon     22942 12 udp6   *:4500                *:*
root     charon     22942 13 udp4   *:500                 *:*
root     charon     22942 14 udp4   *:4500                *:*
root     charon     22942 20 stream /var/run/charon.ctl
root     charon     22942 21 stream /var/run/charon.vici
root     starter    22764 5  dgram  (not connected)
root     nginx      57467 5  tcp4   *:443                 *:*
root     nginx      57467 6  tcp6   *:443                 *:*
root     nginx      57467 7  tcp4   *:80                  *:*
root     nginx      57467 8  tcp6   *:80                  *:*
root     nginx      57350 5  tcp4   *:443                 *:*
root     nginx      57350 6  tcp6   *:443                 *:*
root     nginx      57350 7  tcp4   *:80                  *:*
root     nginx      57350 8  tcp6   *:80                  *:*
root     nginx      57077 5  tcp4   *:443                 *:*
root     nginx      57077 6  tcp6   *:443                 *:*
root     nginx      57077 7  tcp4   *:80                  *:*
root     nginx      57077 8  tcp6   *:80                  *:*
root     dpinger    27696 5  dgram  (not connected)
root     dpinger    27696 6  stream /var/run/dpinger_GW_WAN~192.168.101.40~192.168.101.2.sock
root     devd       415   4  stream /var/run/devd.pipe
root     devd       415   5  seqpac /var/run/devd.seqpacket.pipe
root     check_relo 358   3  stream /var/run/check_reload_status
root     php-fpm    322   3  dgram  (not connected)
root     php-fpm    322   4  udp4   *:*                   *:*
root     php-fpm    322   5  udp6   *:*                   *:*
root     php-fpm    322   13 stream /var/run/php-fpm.socket
root     php-fpm    321   3  dgram  (not connected)
root     php-fpm    321   4  udp4   *:*                   *:*
root     php-fpm    321   5  udp6   *:*                   *:*
root     php-fpm    321   13 stream /var/run/php-fpm.socket
root     php-fpm    321   14 dgram  (not connected)
root     php-fpm    319   3  dgram  (not connected)
root     php-fpm    319   4  udp4   *:*                   *:*
root     php-fpm    319   5  udp6   *:*                   *:*
root     php-fpm    319   15 stream /var/run/php-fpm.socket

netblues

@Hekmil as you see, service unbound is listening on all interfaces.
So nslookup shouldn't be complaining.
This is really strange.

Can you telnet 172.16.1.2 (pfsense lan) on port 53 from pf cli?

Hekmil

@netblues Yes indeed

Yes it works :

netblues

@Hekmil so unbound works.
dig @172.16.1.2 cnn.com

always from cli.

bmeeks

You need to let the unbound DNS server within pfSense do the name resolution for you. Forget your NAT gateway DNS. And remove those two IP addresses from the General Settings tab in pfSense. Out of the box, unbound is ready to operate in resolver mode, which means it will query the root servers and proceed down the domain tree to find the IP for the FQDN. If you want to put any address on the General Settings page in that DNS box, put 127.0.0.1. And uncheck that "DNS Server Override" box. You don't want that in your setup.

Once you do that, go under DIAGNOSTICS > DNS LOOKUP and see if a domain such as "cnn.com" or "google.com" resolves properly. It should.

Once you get that working, then go back and point your AD DNS Server to forward to pfSense instead of that NAT gateway. DNS lookups should then work properly.

Last tip -- sounds like you may not be fully versed in DNS terminology. Make sure you understand the distinction between a DNS resolver and a DNS forwarder. They are not the same. In your case, I think letting unbound on pfSense operate in its normal resolver mode is what you need. However, if you truly want to use DNS forwarding, then you will need to configure that setup in unbound on pfSense.

bmeeks

And you may have an issue with routing while trying to use that NAT gateway DNS server. Does it have a proper route back to your Windows client? In other words, can it find it?

The fact you mentioned pings not working from the Windows client side would indicate either a firewall rule or rules that is blocking it, or there is a routing problem upstream such that the pinged host doesn't know where to send the reply.

First thing to check would be to sniff the WAN interface of pfSense while pinging an external host from the Windows client. Do you see the packet leave the pfSense WAN? If not, check firewall rules and default routes on the Windows client. If you see the packet leave the WAN but no reply comes back, then check upstream routing and/or firewall settings. You can use the built-in sniffer tool available under the DIAGNOSTICS menu on pfSense.

Hekmil

@netblues Result of dig :

@bmeeks Hum, if I follow what you have said I can't resolve anymore any domain. Only theses settings works for me to resolve domain from pfSense :

My AD DNS Server was never forwarding to my NAT gateway, only my pfSense LAN ip address

About terminology I want to use the resolver mode, I only used the forwarding term to mention the redirection from my AD DNS to pfSense.

My guess was also a route issue, but I have no clue how and where to configure it as my NAT settings come from the Virtual Network Editor of VMware Workstation

bmeeks

@Hekmil said in Windows Server DNS Server can't forward to pfSense:

n its DNS server parameters I have set the forward address to my pfSense IP (LAN or WAN interface does it matter ?) which has set my NAT gateway (192.168.101.2) as DNS Server

The DNS setting in that Window you show in your screen cap only affects lookups done from the firewall console. Stated another way, this tells the local DNS client on the firewall (not server) which DNS server to use for lookups the firewall itself is doing (like from that DIAGNOSTICS menu window).

The only time the IP addresses put on this screen matter to unbound (and external clients using pfSense for their DNS lookups) is when unbound is configured to use forwarding mode. There is a check box on the DNS Resolver page for turning on forwarding.

Since resolving does not work, perhaps someplace upstream firewall rules are restricting DNS lookups to only be allowed when originating from the 192.168.101.2 server. So unbound in resolving mode is getting blocked. If that is the case, turn on forwarding mode with unbound and see if that works.

Hekmil

@bmeeks I'm not sure which screen cap you are mentionning, the Geneal settings right ? I'm getting a bit confused sorry due to many information here.

So I should keep the same configuration but turning off Resolver and on Forwarder to see if it works (but with a nslookup on the Windows Server)?

bmeeks

@Hekmil said in Windows Server DNS Server can't forward to pfSense:

@bmeeks I'm not sure which screen cap you are mentionning, the Geneal settings right ? I'm getting a bit confused sorry due to many information here.

So I should keep the same configuration but turning off Resolver and on Forwarder to see if it works (but with a nslookup on the Windows Server)?

The DNS Settings on the pfSense GENERAL SETTINGS screen (that box where you have put in the 192.168.101.2 server).

pfSense now comes with two different DNS server components. The new one is unbound, and this program can be either a resolver or a forwarder. The old DNS component is dnsmasq, and it can only be a forwarder. The default out-of-the-box configuration of pfSense is with unbound (the DNS Resolver) enabled and operating in resolver mode. Unless you put something in those DNS boxes on the General Setup page, the firewall will use the local unbound DNS Resolver for name lookups, and the DNS Resolver will attempt to resolve with the DNS root servers by default.

The old dnsmasq DNS Forwarder is disabled by default now. You really don't want to use it. It is under SERVICES > DNS FORWARDER. It should be disabled. You can't run it and the Resolver at the same as both will try to use the same port 53 to listen for DNS requests.

If you want to use unbound in forwarding mode, there is a checkbox on the SERVICES > DNS RESOLVER setup screen to enable forwarding. The help text in that box says that when you enable forwarding unbound will then forward DNS requests to whatever server you have entered on the SYSTEM > GENERAL SETUP tab down in the DNS Server Settings section.

So what I suggested you try is go to SERVICES > DNS RESOLVER. Make sure the checkbox for Enable DNS Resolver is checked. Then scroll down that page to about the middle and check the box for DNS Query Forwarding. The checkbox says "Enable Forwarding Mode".

Since the DNS lookup failed from pfSense when you took out the 192.168.101.2 DNS server, that indicates to me that perhaps something upstream from pfSense is only allowing DNS requests to be handled by that 192.168.101.2 address. So when unbound tries to contact the DNS root servers directly, it is blocked from doing so.

netblues

@bmeeks Even though what you say is valid, however no matter what settings are in dns resolver, (forwarded, root servers etc, ) under no circumstances dig would return no servers can be reached

for example, digging for something non existent on a pf that has access to internet disconnected..

dig @192.168.31.25 pf.dontexist.net

; <<>> DiG 9.11.13-RedHat-9.11.13-5.el8_2 <<>> @192.168.31.25 pf.dontexist.net
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 10679
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;pf.dontexist.net. IN A

;; Query time: 2 msec
;; SERVER: 192.168.31.25#53(192.168.31.25)
;; WHEN: Jul 22 22:49:13 EEST 2020
;; MSG SIZE rcvd: 45

It returns server fail because IT FAILED upstream.

No servers can be reached indicates a local connectivity problem.
and since we have verified that it is the unbound process that listens on port 53, it can't be a dns forwarder issue.

No servers can be reached, means it got nothing back after contacting port 53
Since this is a test environment under vm, I would install a fresh copy of pf, on another machine and I would try digging on its resolver, as a next step.