DNS Stops working

[Gertjan]

Hi,

DNS works from LAN, right after it's installed.

'Then you made some changes and things stopped working.'

I can see that :
You added another interface.
Changed - at least - the only firewall 'pass-all' rule present on the LAN interface.

What are your LAN and QUEST firewall rules ?
Did you change any DNS settings ?

[manjotsc]

@Gertjan
The last two interfaces have no rules.

[Gertjan]

Remove "WAN_DHCP" here ....

The QUEST network seems fine.

[manjotsc]

@Gertjan Just to let you know DNS stops working on Lan, and guest. I have removed the WANDHCP I'll monitor for few days to see if that happens again or not, thanks

[Gertjan]

I guess you know what you did here (LAN) :

DNS traffic is allowed to go to to IP 168.168.40.1 (you did not mention where this IP is : on LAN ? On some other LAN ? - I presume it's some DNS server - looking at the traffic counter, traffic is send to that DNS server)
The alias "Playstation" (You did not mention if the Playstation does work well - presume, looking at the traffic counters, it does show traffic)
Your DNS block rule works .... and that's why you said "DNS stops working".
(so : remove this rule and you'll be fine ^^)

Just a question : take any device on your LAN, a PC, and type

ipconfig /all

What is the DNS it's using ?
Related question : does your DHCP hands over the correct (= 168.168.40.1 )DNS ?

[manjotsc]

@Gertjan 192.168.40.1 is pfsense box ip, I am using it pfblockerng on it, what's why I made those rules, but when DNS stops working PlayStation also are affect, entire lan and guest is effected. This issue doesn't happens all the time, it's like once a week it occurs.

[Gertjan]

@manjotsc said in DNS Stops working:

192.168.40.1 is pfsense box ip

Tip : use the build in alias "Firewall itself" (the first in the list).

@manjotsc said in DNS Stops working:

it's like once a week it occurs.

At that moment, check if unbound, the DNS resolver on pfSense is actually running.
The best way to do that is using console or SSH access, and type

[2.4.4-RELEASE][admin@pfsense.brit-hotel-fumel.net]/root: ps ax | grep unbound
76224  -  S         0:55.87 /usr/local/sbin/lighttpd_pfb -f /var/unbound/pfb_dnsbl_lighty.conf
83945  -  Ss       17:13.80 /usr/local/sbin/unbound -c /var/unbound/unbound.conf
66966  0  S+        0:00.00 grep unbound

As you can see, mine is running for** 17 hours and 13 minutes.

Also, check the GUI DNS logs : was unbound restarted ? How long did it take ?

** edit : see remark @johnpoz below

[johnpoz]

That is showing you cpu time, not elapsed clock time ;)

If you want to see etime you have to call that out..

example - find the pid

[2.4.4-RELEASE][admin@sg4860.local.lan]/root: ps ax | grep unbound
33787  -  Is        0:41.49 /usr/local/sbin/unbound -c /var/unbound/unbound.conf
25758  0  S+        0:00.00 grep unbound
[2.4.4-RELEASE][admin@sg4860.local.lan]/root: ps -p 33787 -o etime
     ELAPSED
  1-23:27:48
[2.4.4-RELEASE][admin@sg4860.local.lan]/root: ps -p 33787 -o etimes
ELAPSED
 170882
[2.4.4-RELEASE][admin@sg4860.local.lan]/root: 

Then ask for etime or etimes (which will be in seconds)

[Gertjan]

Nice - thanks.

[2.4.4-RELEASE][admin@pfsense.brit-hotel-fumel.net]/root: ps ax | grep unbound
76224  -  S         0:55.96 /usr/local/sbin/lighttpd_pfb -f /var/unbound/pfb_dnsbl_lighty.conf
83945  -  Ss       17:22.86 /usr/local/sbin/unbound -c /var/unbound/unbound.conf
98238  0  S+        0:00.00 grep unbound
[2.4.4-RELEASE][admin@pfsense.brit-hotel-fumel.net]/root: ps -p 83945 -o etime
     ELAPSED
  4-00:48:20

4 days .... ok for me.

[manjotsc]

@johnpoz @Gertjan This is what I got,

[manjotsc]

@Gertjan @johnpoz My pfsense box uptime 2 Days 5 Hours and outbound is for been running for 17 mintues, is that wierd?

[johnpoz]

well in means its restarting - do you have it registering dhcp? Did you just make a change to host or domain overrides... Did pfblocker update, etc..

Problem is when restarts cache is lost, while its restarting nothing can respond to dns, etc.

[manjotsc]

@johnpoz @Gertjan Maybe because it set to every hour, for update what's why maybe. And I didn't understand this part " do you have it registering dhcp?" can you tell you check about this, thanks.

[manjotsc]

@Gertjan @johnpoz It started happing again, Now when I start downloading something file large files, DNS stops working.

Thanks,

[Gertjan]

@manjotsc said in DNS Stops working:

" do you have it registering dhcp?

Do you have checked this one :

If so, when a new lease is asked and granted, the Resolver is restarted.
Compare DHCP logs and DNS Resolver log. You can see it happen.

If you have a device that insists in asking a new DHCP lease every xx minutes, then yes, your Resolver get's restarted every xx minutes. Something you do not want at all ...

@manjotsc said in DNS Stops working:

Maybe because it set to every hour,

So you get what you want : a guaranteed Resolver restart every hour.
And the risk that feed servers are blacklisting your download attempts.

@manjotsc said in DNS Stops working:

Now when I start downloading something file large files, DNS stops working.

Loading some file from the net doesn't use the DNS.
In the beginningt, the URL of the file is resolved. The IP connection is made, and packets just stream through the router/firewall.
Whatever the Resolver is doing at that moment, it has nothing to do with this data stream.

If you want to look for system instability :
Remove ALL packages.
Check for 'strange' system messages : enter the console, option 8 and type "dmesg". See if new logs are added. Are they NIC related ?

[manjotsc]

@Gertjan DHCP Registration, is not checked.

[manjotsc]

@Gertjan This is what I am getting on logs,

----------------------------------------------- Before Reboot ---------------------------------------------

--------------------------------------------- After Reboot -------------------------------------------------

[Gertjan]

@manjotsc said in DNS Stops working:

This is what I am getting on logs,

Both logs show a lot of what happens during DNS resolving.
Logging as much info - note that both logs images show lines that all took please in 1 second (!!).
Logging this much info really takes a hit on the system.
DNS resolving over port 853 (TLS) implies huge processing, because everything has to be encrypted - en of course decrypted - re encrypted on the other side. Reply times like 0.120 seconds or 120 milliseconds become 'normal'.
You do have AES-NI, but, still SDNS takes more time then classic DNS.

Do you have to supply 8.8.8.8 and 1.1.1.1 your private DNS info ? Please remember : these are companies. The fact that they don't bill you is because you gave them valuable info. Do you have to ? Did you try other DNS sources, like the official Internet DNS root servers ?

Another thing : do the http://www.dslreports.com/speedtest test.

No A's means : .... would you experience right now .... the WAN connection gets congested.

[manjotsc]

@Gertjan Can you help me find Root DNS servers, I made searchg, couln't find.

Thanks,

[SteveITS]

@manjotsc said in DNS Stops working:

Can you help me find Root DNS servers

If you don't enable "DNS Query Forwarding" in the DNS resolver settings, then pfSense will query Internet root servers by default.
https://docs.netgate.com/pfsense/en/latest/book/services/dns-resolver.html