Weird Unbound problem



  • Pfsense has been working fine for months but with one nagging problem.

    Certain websites will simply not resolve. Full disclosure: I have a VPN running at all times and use Unbound without forwarding.

    So far it's only a couple of websites but they are ones that I actually use. I know that they are active and working as I can reach them from proxies, my mobile, online ping tests etc.

    Logs show that the sites aren't being blocked in any way so I'm not really sure what to look for…..

    Any ideas?

    Oh, here are a couple of the sites just for grins....

    www.dolphin.com

    webapps.dolphin.com


  • Rebel Alliance Global Moderator

    I show those both resolving fine

    dig www.dolphin.com

    ; <<>> DiG 9.10.4-P2 <<>> www.dolphin.com
    ;; global options: +cmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 38169
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1

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

    ;; ANSWER SECTION:
    www.dolphin.com.        600    IN      A      23.21.255.26

    ;; AUTHORITY SECTION:
    dolphin.com.            86400  IN      NS      f1g1ns2.dnspod.net.
    dolphin.com.            86400  IN      NS      f1g1ns1.dnspod.net.

    ;; Query time: 1175 msec
    ;; SERVER: 192.168.9.253#53(192.168.9.253)
    ;; WHEN: Sat Sep 10 10:28:23 Central Daylight Time 2016
    ;; MSG SIZE  rcvd: 114

    dig webapps.dolphin.com

    ; <<>> DiG 9.10.4-P2 <<>> webapps.dolphin.com                           
    ;; global options: +cmd                                                 
    ;; Got answer:                                                           
    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30110               
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1

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

    ;; ANSWER SECTION:                                                       
    webapps.dolphin.com.    600    IN      A      54.227.243.121

    ;; AUTHORITY SECTION:                                                   
    dolphin.com.            86400  IN      NS      f1g1ns1.dnspod.net.     
    dolphin.com.            86400  IN      NS      f1g1ns2.dnspod.net.

    ;; Query time: 620 msec                                                 
    ;; SERVER: 192.168.9.253#53(192.168.9.253)                               
    ;; WHEN: Sat Sep 10 10:28:51 Central Daylight Time 2016                 
    ;; MSG SIZE  rcvd: 118

    When your having an issue, do a simple query does it not resolve?  Do you get an error like servfail of nxdomain or just a timeout?

    Notice that the ttl is only 600 seconds.  So if they have a problem with their dns, or you have a problem with connectivity to their dns using the resolver then you could have issues sure.  While if you using a proxy or some other connection with dns might have it cached?  Or might have different path to their dns or got an answer from their dns because lots and lots of users always calling for it and keeping the dns cache updated, etc.

    You have to actually see what is going on when it fails via a query, then you could directly query their authoritative name servers, do you get a response then, etc.



  • @johnpoz:

    I show those both resolving fine
                                                                             
    When your having an issue, do a simple query does it not resolve?  Do you get an error like servfail of nxdomain or just a timeout?

    Notice that the ttl is only 600 seconds.  So if they have a problem with their dns, or you have a problem with connectivity to their dns using the resolver then you could have issues sure.  While if you using a proxy or some other connection with dns might have it cached?  Or might have different path to their dns or got an answer from their dns because lots and lots of users always calling for it and keeping the dns cache updated, etc.

    You have to actually see what is going on when it fails via a query, then you could directly query their authoritative name servers, do you get a response then, etc.

    Yea, they both resolve out of my network just fine, they def work as you have shown.

    I get a timeout, nothing in logs or anything of the sort.

    I can add a DNS entry manually with IP address and it will work appropriately. If I change my desktop local DNS server to any other DNS server it will resolve fine as well. The problem is with me but I can't seem to narrow it down.

    It's a simple config, just using Unbound and no forwarding. By default Unbound should get it's info from root servers, it almost seems like the root servers are missing info about these websites.

    I'm at a loss as to why only certain websites are affected….



  • Next time you have the same problem go to the console of pfSense or use an SSH terminal session and try to query one of the root servers directly. Like so:

    
    dig @198.41.0.4
    
    

    That IP address is the a.root-servers.net root server. If the query times out then you're probably experiencing the same problem I have from time to time. I haven't yet figured out what the problem is but I suspect that it's something to do with my ISP:

    https://forum.pfsense.org/index.php?topic=109274.msg608415#msg608415


  • Rebel Alliance Global Moderator

    I doubt the root servers are missing info about this domain..  More like their authoritative servers are not answering, or your connection to them is a problem..

    Do a simple trace to these domains when you have an issue.. What do you get back?

    example

    dig www.dolphin.com +trace

    ; <<>> DiG 9.10.4-P2 <<>> www.dolphin.com +trace
    ;; global options: +cmd
    .                      78626  IN      NS      a.root-servers.net.
    .                      78626  IN      NS      m.root-servers.net.
    .                      78626  IN      NS      b.root-servers.net.
    .                      78626  IN      NS      c.root-servers.net.
    .                      78626  IN      NS      i.root-servers.net.
    .                      78626  IN      NS      g.root-servers.net.
    .                      78626  IN      NS      h.root-servers.net.
    .                      78626  IN      NS      j.root-servers.net.
    .                      78626  IN      NS      k.root-servers.net.
    .                      78626  IN      NS      l.root-servers.net.
    .                      78626  IN      NS      f.root-servers.net.
    .                      78626  IN      NS      e.root-servers.net.
    .                      78626  IN      NS      d.root-servers.net.
    .                      78626  IN      RRSIG  NS 8 0 518400 20160924050000 20160911040000 46551 . q5UthNJ4M+Zl2TjfY05SNu5RU57DkjKIXyaWz092XCN0cRaxBbvwy0OT xm2zE2NI36kHVccS2iKPIgDdR6/0DdBaY+f1Ibe0n+y/ipKpoDP
    RqTIu 1Usd9ltQF3c58aD5W+iU/ewkLuhBWnReyO1i12XTNwlHKjJZTKE4fwor gNw=
    ;; Received 397 bytes from 192.168.9.253#53(192.168.9.253) in 2 ms

    com.                    172800  IN      NS      a.gtld-servers.net.
    com.                    172800  IN      NS      b.gtld-servers.net.
    com.                    172800  IN      NS      c.gtld-servers.net.
    com.                    172800  IN      NS      d.gtld-servers.net.
    com.                    172800  IN      NS      e.gtld-servers.net.
    com.                    172800  IN      NS      f.gtld-servers.net.
    com.                    172800  IN      NS      g.gtld-servers.net.
    com.                    172800  IN      NS      h.gtld-servers.net.
    com.                    172800  IN      NS      i.gtld-servers.net.
    com.                    172800  IN      NS      j.gtld-servers.net.
    com.                    172800  IN      NS      k.gtld-servers.net.
    com.                    172800  IN      NS      l.gtld-servers.net.
    com.                    172800  IN      NS      m.gtld-servers.net.
    com.                    86400  IN      DS      30909 8 2 E2D3C916F6DEEAC73294E8268FB5885044A833FC5459588F4A9184CF C41A5766
    com.                    86400  IN      RRSIG  DS 8 1 86400 20160924050000 20160911040000 46551 . XXFl3T8AiPbwLWJlhgoI7BkW9Jg1WFxziiVt4V1umAaUGhwpsbyy1rmq uOt/Mdru1WeaguvpA7IQR30Cix9XU1QekHayQjahH+XAAXeHTtE9
    3rRS otpJ/SxCBfQco2vwq801wOyAI2fPn/Wxpk2HgT+8rA5cyte+MfHfqqBt GZc=
    ;; Received 739 bytes from 192.203.230.10#53(e.root-servers.net) in 11 ms

    dolphin.com.            172800  IN      NS      f1g1ns1.dnspod.net.
    dolphin.com.            172800  IN      NS      f1g1ns2.dnspod.net.
    CK0POJMG874LJREF7EFN8430QVIT8BSM.com. 86400 IN NSEC3 1 1 0 - CK0Q1GIN43N1ARRC9OSM6QPQR81H5M9A  NS SOA RRSIG DNSKEY NSEC3PARAM
    CK0POJMG874LJREF7EFN8430QVIT8BSM.com. 86400 IN RRSIG NSEC3 8 2 86400 20160915044336 20160908033336 27452 com. xNERKmnAlkb3XiEf76OahP52D10WKZLu7GcWpYhVT4be0SBbmq9Kn+XV AnaMG/Ywu1/4VPyMfDxnw+XJLMXLn3NJN7TbNLA9Z
    0TqcpbRZcnTq1Na cO9/iuAx32Oaf5pbJIwuSS7HAhfDY4tahpYuSYDz8xOQzyf5W6wnjWAL sAc=
    Q05059R7K3JFV1UDP1G1SM61I57CKHL2.com. 86400 IN NSEC3 1 1 0 - Q051JGOH12HHFA74IF5LTR5A3K8NGAAK  NS DS RRSIG
    Q05059R7K3JFV1UDP1G1SM61I57CKHL2.com. 86400 IN RRSIG NSEC3 8 2 86400 20160915044056 20160908033056 27452 com. NN6PIwgJuLkL0N6ZhwcHFUO7fe0K7AHyMTXoUITg1qjzpF5LXgko/5f9 BFh+mHWAMpwn2Yhu/zutJbMxZzSbo/ggLw43Onuq7
    H67IOpG8zdIl+St 1D1uP/q8lrRkg9nY9XA8yuluAKYfS3EkBaUs/XE7HC7I1mA7w09HpoiV cgI=
    ;; Received 727 bytes from 192.5.6.30#53(a.gtld-servers.net) in 11 ms

    www.dolphin.com.        600    IN      A      23.21.255.26
    dolphin.com.            86400  IN      NS      f1g1ns2.dnspod.net.
    dolphin.com.            86400  IN      NS      f1g1ns1.dnspod.net.
    ;; Received 124 bytes from 182.140.167.188#53(f1g1ns2.dnspod.net) in 379 ms