Understanding SERVFAIL (for google)

[Bill Moseley]

9.2.2-P3-1 on Debian Stable.

I'm trying to understand how to debug this.

    moseley at mardy:~$ dig  www.google.com.

    ; <<>> DiG 9.2.2-P3 <<>> www.google.com.
    ;; global options:  printcmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 23596
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

    ;; QUESTION SECTION:
    ;www.google.com.                        IN      A

    ;; Query time: 1 msec
    ;; SERVER: 192.168.1.1#53(192.168.1.1)
    ;; WHEN: Wed Mar 30 16:57:09 2005
    ;; MSG SIZE  rcvd: 32

Yet a few minutes later the same query works.  This is new in the last
week, so it seems, and nothing has been changed on that server.  So,
what I'm looking for is tips on how to debug the SERVFAIL while it's
happening.

I am finding other similar posts about intermittent SERVFAIL (at least
when I can search google...), but I'm not seeing an explanation.


While I'm getting SERVFAIL I can run this without any problem:

    moseley at mardy:~$ dig @ns1.google.com. www.l.google.com.


Probably not too helpful, but here's a +trace:

    ; <<>> DiG 9.2.2-P3 <<>> +trace www.google.com
    ;; global options:  printcmd
    .                       302772  IN      NS      I.ROOT-SERVERS.NET.
    .                       302772  IN      NS      J.ROOT-SERVERS.NET.
    .                       302772  IN      NS      K.ROOT-SERVERS.NET.
    .                       302772  IN      NS      L.ROOT-SERVERS.NET.
    .                       302772  IN      NS      M.ROOT-SERVERS.NET.
    .                       302772  IN      NS      A.ROOT-SERVERS.NET.
    .                       302772  IN      NS      B.ROOT-SERVERS.NET.
    .                       302772  IN      NS      C.ROOT-SERVERS.NET.
    .                       302772  IN      NS      D.ROOT-SERVERS.NET.
    .                       302772  IN      NS      E.ROOT-SERVERS.NET.
    .                       302772  IN      NS      F.ROOT-SERVERS.NET.
    .                       302772  IN      NS      G.ROOT-SERVERS.NET.
    .                       302772  IN      NS      H.ROOT-SERVERS.NET.
    ;; Received 372 bytes from 192.168.1.1#53(192.168.1.1) in 1 ms

    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.                    172800  IN      NS      A.GTLD-SERVERS.NET.
    ;; Received 504 bytes from 192.36.148.17#53(I.ROOT-SERVERS.NET) in 156 ms

    google.com.             172800  IN      NS      ns1.google.com.
    google.com.             172800  IN      NS      ns2.google.com.
    google.com.             172800  IN      NS      ns3.google.com.
    google.com.             172800  IN      NS      ns4.google.com.
    ;; Received 168 bytes from 192.33.14.30#53(B.GTLD-SERVERS.NET) in 198 ms

    www.google.com.         900     IN      CNAME   www.l.google.com.
    l.google.com.           86400   IN      NS      a.l.google.com.
    l.google.com.           86400   IN      NS      b.l.google.com.
    l.google.com.           86400   IN      NS      c.l.google.com.
    l.google.com.           86400   IN      NS      d.l.google.com.
    ;; Received 180 bytes from 216.239.32.10#53(ns1.google.com) in 53 ms


Then trying again:


    moseley at mardy:~$ dig www.l.google.com.

    ; <<>> DiG 9.2.2-P3 <<>> www.l.google.com.
    ;; global options:  printcmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 58011
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

    ;; QUESTION SECTION:
    ;www.l.google.com.              IN      A

    ;; Query time: 1 msec
    ;; SERVER: 192.168.1.1#53(192.168.1.1)
    ;; WHEN: Wed Mar 30 16:57:32 2005
    ;; MSG SIZE  rcvd: 34



-- 
Bill Moseley
moseley at hank.org