hostname-check

This script checks RR of a zone which have a QTYPE with an external (out-of-bailiwick) hostname. It will check if these hostnames are resolvable or in the case of QTYPE NS, whether there is mismatch between parent and child zone. Specifically, this scripts supports rdata hostname checks of the QTYPEs NS, CNAME, MX, SRV and DNAME.

The script sends DNS queries to your local resolver but also to authoritative name servers directly (only needed for zone apex NS rrset checks). Zone apex NS rrset checks are skipped if queries to authoritative name servers fail.

Dependencies

• python3
• dnspython

If you have installed python you should be able to install dnsypthon with the command pip3:

pip3 install dnspython

Usage

./hostname-check.py OPTIONS [-n address|-i zonefile] -o origin
-o origin     zone origin e.g. switch.ch
-n address    get zone via zone transfer from nameserver ip address
-i zonefile   read zone from file (BIND zone format)

OPTIONS:
-r address    recursive resolver ip address instead of system default
-k keyfile    specify tsig key file for zone transfer access
-x policy     comma seperated list of qtype to check. default if not
              specified: NS,MX,CNAME,SRV,DNAME
-t timeout    DNS query timeout (default 3 sec)
-v            verbose output (debugging)
-h            print this help

Notes:

• tsig key file expects a BIND key file (See also BIND ARM)
• The script sends DNS queries to your local resolver but also to authoritative name servers directly

License

Licensed under the term of MIT License.

Alternatives

You might also want to check out the following tools with the same goal:

• https://github.com/yahoo/SubdomainSleuth