DNS Tools

• nslookup
• dig v2.0
• doc v2.0
• dnswalk v1.8.3
• nslint v1.1

All but nslint come with the bind distribution

ftp sites :
gatekeeper.dec.com:/pub/BSD/bind/4.9/4.9.*.tar.Z

Or just for dig separately :
ftp.uu.net:/networking/ip/dns/dig.2.0.tar.Z

And for dnswalk separately :
ftp.uu.net:/networking/ip/dns/dnswalk/dnswalk-1.8.3.tar.Z

Interactive/Basic Query Tools

Analysis/Trouble Finding Tools

dnswalk v1.8.3
Perl scripts to try to find problems with DNS

nslint v1.1
C program to analyze local DNS Tables

Note :both doc and dnswalk require dig

Sample Output from Dig

[bundy:jeff:/home2/jeff] dig cnet-pnw.com
 
; $lt;$lt;>> DiG 2.0 $lt;$lt;>> cnet-pnw.com 
;; ->>HEADER$lt;$lt;- opcode: QUERY , status: NOERROR, id: 6
;; flags: qr aa rd ra ; Ques: 1, Ans: 0, Auth: 0, Addit: 0
;; QUESTIONS: 
;;      cnet-pnw.com, type = A, class = IN
  
;; Sent 1 pkts, answer found in time: 1 msec 
;; FROM: bundy to SERVER: default -- 199.182.118.61
;; WHEN: Mon Jan  9 10:00:19 1995
;; MSG SIZE  sent: 30  rcvd: 30


[bundy:jeff:/home2/jeff] dig netcom.com
 
; $lt;$lt;>> DiG 2.0 $lt;$lt;>> netcom.com 
;; ->>HEADER$lt;$lt;- opcode: QUERY , status: NOERROR, id: 6
;; flags: qr rd ra ; Ques: 1, Ans: 1, Auth: 2, Addit: 2
;; QUESTIONS: 
;;      netcom.com, type = A, class = IN
  
;; ANSWERS:
netcom.com.     1822    A       192.100.81.100
 
;; AUTHORITY RECORDS:
netcom.com.     125268  NS      NETCOMSV.NETCOM.COM.
netcom.com.     125268  NS      NS.NETCOM.COM.
   
;; ADDITIONAL RECORDS:
NETCOMSV.NETCOM.COM.    126695  A       192.100.81.101
NS.NETCOM.COM.  126695  A       192.100.81.105
 
;; Sent 1 pkts, answer found in time: 1 msec 
;; FROM: bundy to SERVER: default -- 199.182.118.61
;; WHEN: Mon Jan  9 10:01:19 1995
;; MSG SIZE  sent: 28  rcvd: 126


Other Queries that can be done :

          a      T_A      network address
          any    T_ANY    all/any information about specified domain
          mx     T_MX     mail exchanger for the domain
          ns     T_NS     name servers
          soa    T_SOA    zone of authority record
          hinfo  T_HINFO  host information
          axfr   T_AXFR   zone transfer
                          (must ask an authoritative server)
          txt    T_TXT    arbitrary number of strings
                          (not yet supported by BIND)

Sample Use of dnswalk

[bundy:jeff:/home2/jeff/src/dnswalk] cat do-dnswalk 
#!/bin/sh
# Here's an example script for a hostmaster of a large site
# to automate the process
# try adding '-F' here once just to see what pops up
flags='-F -r -d'
logfile=cnet.errors
trap "" 2 15;
exec $gt; ${logfile}
./dnswalk ${flags} $* cnet-pnw.com.
./dnswalk ${flags} $* 118.182.199.in-addr.arpa.

$lt;b$gt;Output$lt;/b$gt;

Checking cnet-pnw.com.
SOA=bundy.cnet-pnw.com. contact=jeff.bundy.cnet-pnw.com.
 cnet-pnw.com. NS bundy.cnet-pnw.com.: CNAME (to bundy.cnet-pnw.com.)
 cnet-pnw.com. NS ns.netcom.com.: CNAME (to ns.netcom.com.)
 ns.netcom.com. A 192.100.81.105: points to nntp.netcom.com
 cnet-pnw.com. MX 40 bundy.cnet-pnw.com.: CNAME (to bundy.cnet-pnw.com.)
 loghost.cnet-pnw.com. CNAME bundy.cnet-pnw.com.: CNAME (to bundy.cnet-pnw.com.)
 mailhost.cnet-pnw.com. CNAME bundy.cnet-pnw.com.: CNAME (to bundy.cnet-pnw.com.)
Checking 118.182.199.in-addr.arpa.
SOA=bundy.cnet-pnw.com. contact=jeff.bundy.cnet-pnw.com.
 118.182.199.IN-ADDR.ARPA. NS bundy.cnet-pnw.com.: CNAME (to bundy.cnet-pnw.com.)
 118.182.199.IN-ADDR.ARPA. NS ns.netcom.com.: CNAME (to ns.netcom.com.)
 ns.netcom.com. A 192.100.81.105: points to nntp.netcom.com
 1.118.182.199.IN-ADDR.ARPA. PTR annex1.cnet-pnw.com.: CNAME (to annex1.cnet-pnw.com.)
 2.118.182.199.IN-ADDR.ARPA. PTR annex2.cnet-pnw.com.: CNAME (to annex2.cnet-pnw.com.)
 68.118.182.199.IN-ADDR.ARPA. PTR oakridge.cnet-pnw.com.: CNAME (to oakridge.cnet-pnw.com.)
 81.118.182.199.IN-ADDR.ARPA. PTR fawn.cnet-pnw.com.: CNAME (to fawn.cnet-pnw.com.)
 83.118.182.199.IN-ADDR.ARPA. PTR genghis.cnet-pnw.com.: CNAME (to genghis.cnet-pnw.com.)

Sample output from nslint

[bundy:jeff:/home2/jeff/src/nslint] ./nslint
nslint: missing "ptr": localhost.cnet.com. -> 127.0.0.1
nslint: illegal hostname SEATTLE.cnet-pnw.com. (starts with non-alpha)
nslint: illegal hostname SEATTLE.cnet-pnw.com. ('E' illegal character)
nslint: illegal hostname DALLAS.cnet.com. (starts with non-alpha)
nslint: illegal hostname DALLAS.cnet.com. ('A' illegal character)
nslint: missing "ptr": bundy.cnet.com. -> 199.182.118.61
nslint: illegal hostname cnet_demo.cnet.com. ('_' illegal character)
nslint: illegal hostname @IN.0.0.127.IN-ADDR.ARPA. (starts with non-alpha)
nslint: illegal hostname @IN.0.0.127.IN-ADDR.ARPA. ('I' illegal character)
nslint: illegal hostname DALLAS.cnet-pnw.com. (starts with non-alpha)
nslint: illegal hostname DALLAS.cnet-pnw.com. ('A' illegal character)
nslint: illegal hostname bundy_dal.cnet.com. ('_' illegal character)
nslint: 127.0.0.1 in use by localhost.cnet.com. and localhost.cnet-pnw.com.
nslint: 199.182.118.61 in use by bundy.cnet-pnw.com. and bundy.cnet.com.