Redirect DNS: Question.
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@yogi_en said in Redirect DNS: Question.:
Source clients IPs and the DNS server IPs needs to be on the same subnet for this redirection to work. Is that correct?
No.. Lets see your redirection rule. Its normally other way around if you redirect to something in the same network.
I can ping the DNS server in LAN1 from my LAN devices. dig also works
In the redirection rules you linked to you redirect to pfsense itself unbound. If you try and redirect say 8.8.8.8 and to something else on some other network. You run into the problem where the client will balk at the answer because it sent to mac address xyz, your gateway (pfsense). But it got an answer from some other mac when the redirection is to something in the same network..
Like so..
When I tell the client to ask 8.8.8.8 and it redirects to something on the same network as the client, dns will say hey something not right and not work..
In the above example my client is on the same 192.168.3 network..
In the doc you linked too your suppose to redirect to loopback, so that never happens. If where your redirecting has access to your client via a different path than pfsense it would most likely give you that problem.
If I do the same sort of redirection to dns on my 192.168.3 network from my lan network 192.168.9/24 and a client on lan asks it works just fine
You can tell that was redirected because there is no way 8.8.8.8 would know about my local resource at 192.168.9.253 (pfsense name)
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@johnpoz Thanks. More details.
My LAN is 192.168.1.0/24. DNS Server in LAN is 192.168.1.10
MY LAN1 ( IOT ) 192.168.5.0/24. DNS Server in IOT is 192.168.5.25My Working Redirection Rule is below:
I limited the rule only to 192.168.1.60 which is my laptop.
This works fine. dig produces the following output.
My NOT working rule is below.
DNS server is changed here.dig produces the following output.
As you can see the redirection is not working.
I can manually set 192.168.5.25 as DNS server for my LAN network. This works fine. Any help is appreciated.
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@yogi_en how do you think that is working fine - dig didn't give you an answer and clearly states hey this answer is from unexpected source..
That second one is the one working - you get an answer.. because it redirected your traffic you sent to 1.1.1.1 to your dns server on the other network.
Ask 1.1.1.1 for something only your local dns would know, like I did above asking for something that would resolve to one of my local IPs only - google dns sure doesn't have a clue about my local resources and would return a NX..
Like this when its not redirected
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The first one is working because , I can see the DNS queries log in my pihole which is 192.168.1.10. Though dig didn't give answer browsing works fine and pihole logs are seen as expected.
For the second one, the DNS query actually goes to 1.1.1.1 as I don't see any query logs in my pihole.
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@yogi_en dude while the redirection might be working your not going to be able to get any DNS..
Your 2nd one is actually the one working, because you got an answer.
If you don't want dns to 1.1.1.1 to work, then just block it vs redirecting it.
Here I put the redirection back, and can see that pihole got it an answered it..
Maybe you just missed the log entry.. There can be a lot of them - so maybe you just didn't see it.. But your first setup is never going to work for dns since any sane client shouldn't accept that query.. Maybe your dns client of your os would? But do a simple query for redirection that only your local dns can answer.
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Sorry, I am confused. In the first case the DNS is supposed to get redirected to 192.168.1.10. This works fine. I can browse , ping etc. All the queries gets redirected to 192.168.1.10 which I can see from the pihole logs.
For the second case ( not working ), I expect all the DNS to get redirected to 192.168.5.25, which is not working. It still goes to 1.1.1.1 as shown by dig output. Also I do not see the queries in 192.168.5.25 DNS server.
I didn't miss the log entry. I checked multiple times to ensure that.
My question is not about blocking 1.1.1.1. I want to force certain clients to use only the DNS server which I provide. This works fine if clients and DNS server is on the same subnet ( working for the last couple of years with out any issue ). Issue started happening when I created a new DNS server in a different subnet.
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@yogi_en said in Redirect DNS: Question.:
It still goes to 1.1.1.1 as shown by dig output. Also I do not see the queries in 192.168.5.25 DNS server.
Why do you say that? The client asked 1.1.1.1 he doesn't know that your 5.25 box answered.. That exactly how it should look in a working redirection.
While your dns on your os might accept that redirected query - it shouldn't!! that is why dig complains.. It sent the query to its gateway going to 1.1.1.1 mac address of the gateway. But it got a response from some other mac at a different IP other than its gateway. Any sane and secure dns client would complain about that and shouldn't work, jsut like dig is going - telling you hey something not right here!!
Redirection to dns on another vlan works just fine.. As I have shown, do a sniff of the traffic you want.. But no your dig wouldn't complain about it, because the answer came back from the mac address it sent it too (pfsense).. So it thinks that answer came from who he asked 1.1.1.1
another clue you were redirected - do you really think 1.1.1.1 answered in 4 ms?
If you got an answer from 1.1.1.1 in 4ms you have a really nice connection to the internet and are really freaking close to one of the anycast servers for cloudflare ;)
I'm close and all with 14ms to 1.1.1.1
But 4ms is a little too fast ;) again simple test query something to 1.1.1.1 that only local dns can respond with, some local fqdn.. that 1.1.1.1 would have no clue about.
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Thanks. I can give you multiple example to show why the second is working.
See the below dig. If the redirections works fine ( Second case ), I should see this logs in the DNS server of 192.168.5.25. However I see this query as part of 192.168.1.10.
Second example:
hps01 is local hostname only known 192.168.1.10 ( added via LocalDNS feature of pihole ). This resolves fine which means redirection to 192.168.5.25 is not working.
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@yogi_en dude I don't know how else I can explain it too you..
But a query for hps01. should never work asking anything because its not a fqdn.. Plain and simple - that tells me your dns is borked to be honest.
Query something only this 5.25 would know, now do a query to 1.1.1.1 after setting up redirection.. If your redirect is correct you would get an answer, if you ask 1.1.1.1 directly - then it would send back NX as I have shown multiple times already.
See my edit - you got a answer from 1.1.1.1 in 4ms -- really?
edit: Look in your state table when you do a query that should be redirected - example here is my client asking 8.8.8.8 you can see from the state table it was redirect to my pihole on 192.168.3.10
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OK. Thanks for the help and pointers. Let me do some more experiments before I get back to you.
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@yogi_en here to help - any questions just ask.. State table is quick easy verification to validate your redirection work. But also just asking something there is no way 1.1.1.1 would have an answer for is another, that only your local dns could answer.
Also response times in the really low ms range, like your 4ms you posted is another huge hint that it was redirected. If your getting 4ms response time from 1.1.1.1 that is crazy fast ;)
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@johnpoz Some more info which might help us in debugging.
You are right about second scenario. It works in some situations. I have added a local DNS record hpss.localdomain in 192.168.5.25. Only 192.168.5.25 knows about this.
The following works as expected.
However the below doesn't work as expected. Here I am expecting the redirection to happen. However DNS server used is still 192.168.1.10.
Any thoughts?
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@yogi_en said in Redirect DNS: Question.:
Any thoughts?
Not sure what your asking - looks to be working to me.
DNS server used is still 192.168.1.10.
Well yeah you clearly directly asked for 192.168.1.10 - if your on the same network, how would pfsense be involved in that conversation to redirect you.
Pfsense is never going to be involved in traffic between device the same network. It is a router, ie gateway off a network to get to other networks. When 192.168.1.x wants to talk to 192.168.1.y pfsense has nothing to do with that conversation. How could it ever possible redirect anything?
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Thanks. My use case is like this.
I have a set of clients in LAN. I want all these clients to use DNS Server in LAN1 ( 192.168.5.25 ) no matter what the client's DNS settings are. Is there any way to achieve this in pfsense?
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@yogi_en yeah if the client is set to use something that is off your 192.168.1 network, then you could redirect them to who you want on pfsense. But if they happen to ask dns on the same 192.168.1 network there is nothing pfsense can do about that.
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Thanks got it. Your replies were quite informative and I learned many things because of that. I have been trying to re-direct the DNS which is on the same subnet which I understood now is not possible. Appreciate the all your help and time.
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@yogi_en glad I could be of help.. Here all the time ;)
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I have a totally unrelated question.
I need to use the latest version of unbound from FreeBSD. The version that is currently available with 2.5.2 doesn't support 'EDNS client subnet' as mentioned here https://redmine.pfsense.org/issues/11921. I need this feature to resolve the local IPs behind NAT when running the DNS server ( pihole ) in cloud.
Dnsmasq support this feature and it works well.
It looks like the FreeBSD version of unbound support this Couple of questions.
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How can I update unbound to the latest version from FreeBSD? Is there any risk associated with this?
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Or should I use BIND for this?
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@yogi_en so if the bind version that is part of 2.5.2 works for you - you could use that.
But 2.6 which is out as RC and from my understanding of announcements should come out by end of Jan as release. There was mention of 22.01 dropping by end of the month, and "assume" 2.6 would be in line with that as well.
2.6 rc currently has unbound 1.13.2
As to risk of just using some freebsd version that is not in the pfsense repo, while that is always an "option" Prob not a good idea.. I know there was some "fixes" or improvements with edns and unbound 1.14, but I have not heard anything about when that might be included in pfsense. I am not currently doing anything with that or even played with it at all, so I am unsure if that is something you could do with a 1.13 version or if you need to be at least 1.14 of unbound?
Just as a point of discussion, if there is something want/need that is not supported in some service be it dhcp or dns as examples in the version of pfsense that is current. Nothing saying you can not just fire up those services on a pi or vm or shoot even a docker, etc..
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Thanks again for the informative replies!. I think I will go ahead and use BIND. I was hesitant because, I have never used BIND earlier, so there is a learning curve for me.
