Bogons via DNS

We provide bogon tracking through DNS via several reversed-IP zones. These zones are queried by reversing the octets of an IPv4 address (or nibbles of an IPv6 address) and appending a zone name, much like reverse DNS ( and and DNSBL queries.

If the IP address represented by a given query is a bogon, the response will be an A RR of You may also query for a TXT RR, which will indicate the bogon prefix within which the given address resides (no TXT record will be present for non-bogon queries).

The available Bogon DNS zones are:

The traditional IPv4 bogon prefixes; Martian (reserved) prefixes plus those /8 networks not allocated to an RIR by IANA.​

IPv4 “fullbogons”, encompassing the traditional IPv4 bogon prefixes from as well as prefixes that have been allocated to RIRs but not yet assigned by those RIRs to ISPs, end-users, etc.​

IPv6 “fullbogons”, all IPv6 prefixes that have not been allocated to RIRs and that have not been assigned by RIRs to ISPs, end-users, etc.


We can verify that is part of a bogon prefix:

dig +short

We can verify that  is a bogon prefix:

dig +short

We can check the IPv4 fullbogons zone for  , and check what prefix it is part of:

dig +short

dig +short TXT


We can check the IPv6 fullbogons zone for  2001:DB8:FEEB:DEEF::242  , and see what prefix it is part of, but it won’t be pretty because we have to expand out all of the zeroes to do it:

dig +short TXT "2001:db8::/29"

dig +short

(Note that the prefix returned for the TXT query above will likely change in the future; the IPv6 documentation prefix is actually 2001:db8::/32, it is aggregated as a /29 in the IPv6 fullbogons feed because the immediately adjacent prefixes have not yet been assigned to any end-users.)


Zone transfers of the entire zone are permitted,, and This can be accomplished with the following syntax:

dig axfr dig axfr dig axfr

Zone transfers are not currently offered for the zones.