Unbound DNS Resolver - Not caching?

johnpoz

Depends.. If you you have domain.lan, and you have something that adds suffix do you want that searching going out to the roots to try and look up?

So for example if your client asks for cnn.com.domain.lan do you want unbound to try and find that? Or do you want it to respond with NX since it has no record for it?

If you look for nohostyouhave.domain.lan do you want unbound to ask roots trying to find it?

So I run static, with SOA entry.. So when I try and lookup something that is not in my dns but in my domain local.lan I get this.. so if something gets looked up and for whatever reason the app or whatever adds my local suffix it to it, unbound just sends back NX vs sending it on anywhere. 2nd pic example

All comes down to what you want..

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jim82

I would like to have it configured, so I don't send those request out. So I guess "Static" with SOA is the way to go.

How to add SOA for my domain in unbound?

jim82

Another thing, that I'm hoping you might have the answer to :)

After enabling the DNS resolver, I'm getting hundreds of firewall entries concerning DNS.

The source IP's seem to be DNS servers operated by my ISP, but I don't know why they're trying to return a query to me on a non-established port. I'm not using the ISP DNS servers, I should be querying root servers only.

I have attached a screenshot of the firewall log.

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johnpoz

You can create a SOA record in the advanced option.. Attached you will see mine.

As to those blocks.. I would sniff on your wan and see what is going on.. Grab those packets and open them up in wireshark, etc.. What is the data in them? If something was actually creating the queries, then they shouldn't be blocked they should be allowed, etc. So yeah its a bit odd.. Maybe your isp is trying to do some sort of intercept on your dns queries and sending them back? So your not actually talking to roots.. But normally in this case queries fail..

As I said before watching dns traffic on your wan with a sniffer can be quite enlightening to what is actually going on.

The include is something you don't need, that is me just loading up domains I redirect to loopback to block ad domains.. pfblocker does such a thing, but it redirects to service running on pfsense that serves up 1x1 image, not something I need/want.. So I just send back loopback if anything tries to lookup a ad domain, etc.


> dig something.zmedia.com

; <<>> DiG 9.10.3-P4 <<>> something.zmedia.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30873
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;something.zmedia.com.          IN      A

;; ANSWER SECTION:
something.zmedia.com.   3600    IN      A       127.0.0.1

;; Query time: 0 msec
;; SERVER: 192.168.9.253#53(192.168.9.253)
;; WHEN: Sun May 22 06:55:20 Central Daylight Time 2016
;; MSG SIZE  rcvd: 65

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jim82

Thanks a million. I actually started a capture and while analysing your reply ticked in :)

I will try the SOA record, do I also need to add the "root.local.lan" you have in the SOA?

EDIT: mine looks like this now local-data: "domain.lan. 10800 IN SOA pfsense.domain.lan. 1 3600 1200 604800 10800"

As to the weird DNS.

I had a firewall alias with a friends DDNS address which I resolved to allow him access to my plex server. According to the packet capture, that DDNS address does not exist. The following ip addresses was hitting my WAN from port 53 with a reply:

195.215.95.7
195.215.95.8
195.215.95.12
195.215.95.11
195.215.95.6

I have attached the wireshark screenshot.

Removing the DDNS address from the alias has solved that problem :)

You're the man, might consider dropping by with that bourbon :D :P

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johnpoz

Well a SOA needs an email address to be valid atleast I believe it does, can be anything you want it to be. I don't think its valid without that? Your saying it loads and gets returned when you look up something that is not a valid record in your domain?

The SOA resource record contains the following information:

Source host - The host where the file was created.

Contact e-mail - The e-mail address of the person responsible for administering the domain's zone file. Note that a "." is used instead of an "@" in the e-mail name.

Serial number - The revision number of this zone file. Increment this number each time the zone file is changed. It is important to increment this value each time a change is made, so that the changes will be distributed to any secondary DNS servers. (since you don't have any secondary servers there will be no need to change your serial number going forward)

Refresh Time - The time, in seconds, a secondary DNS server waits before querying the primary DNS server's SOA record to check for changes. When the refresh time expires, the secondary DNS server requests a copy of the current SOA record from the primary. The primary DNS server complies with this request. The secondary DNS server compares the serial number of the primary DNS server's current SOA record and the serial number in it's own SOA record. If they are different, the secondary DNS server will request a zone transfer from the primary DNS server. The default value is 3,600.

Retry time - The time, in seconds, a secondary server waits before retrying a failed zone transfer. Normally, the retry time is less than the refresh time. The default value is 600.

Expire time - The time, in seconds, that a secondary server will keep trying to complete a zone transfer. If this time expires prior to a successful zone transfer, the secondary server will expire its zone file. This means the secondary will stop answering queries, as it considers its data too old to be reliable. The default value is 86,400.

Minimum TTL - The minimum time-to-live value applies to all resource records in the zone file. This value is supplied in query responses to inform other servers how long they should keep the data in cache. The default value is 3,600.

So those servers were answering that the record you were asking them about is NX? What were they returning exactly, was unbound actually sending them a query? So when your aliases were updating they were asking them about the record? So what do you have pfsense pointing to for dns? Only ns that pfsense can use in my setup is itself (resolver) it has no entries in general, it only has 127.0.0.1 listed as dns. And I don't allow dhcp on the wan to overwrite any dns info.

If you were actually sending them a query, not sure why it would of been listed as blocked in your firewall log? If they were sending you traffic that pfsense did not expect, then sure it should be blocked.

jim82

Thanks for your reply.

So you are saying that my SOA record local-data: "domain.lan. 10800 IN SOA pfsense.domain.lan. 1 3600 1200 604800 10800" is missing information? Can you guide me through how to add the relevant data to the entry?

As to the weird DNS. I will have to enable that alias once again and check. I also wondered why I was hammered with replies. From what I remember, I had not sent a query out.

On my General page in pfSense I have listed some DNS servers, see screenshot.

EDIT: Added screenshots of the same queries you did in your post above. (https://forum.pfsense.org/index.php?topic=112160.msg625069#msg625069)

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johnpoz

there is no point to those other servers if your wanting all queries to go through unbound. If pfsense asks those server its not going to be able to resolve your local entries.

Yeah see your not getting a SOA returned when you ask for something that is not in your domain, so yeah that SOA is not loading or is invalid because its missing your email address.

Just add your email address to your record. Whatever email you want, does not have to be valid to be honest, just replace the @ with . So the way mine reads is root@local.lan

ocal-data: "domain.lan. 10800 IN SOA pfsense.domain.lan. root.domain.lan. 1 3600 1200 604800 10800"

So you see when I ask for something that is no in my local.lan I get back a SOA along with the NX.

There is nothing say you need to do this, it just makes it easy to see right away that what you queried was really NX and what the authoritative server was is all.

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jim82

Excellent, looks like the SOA is now working, see screenshot.

Also I have removed all my ISP/Google DNS from the general page.

Thanks again for your kind assistance :)

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johnpoz

looks like you did the query right from pfsense, but yup sure that looks like your getting SOA back with your NX. So now when you have something that adds your suffix to something your looking for it will not go paste pfsense.

jim82

Tried from a Windows client, looks good to me :)

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