Companies using public IP space owned by others for internal routing

Jens Link lists at
Sun Dec 17 23:25:29 CST 2017

Matt Hoppes <mattlists at> writes:

> Had a previous employee or I discovered it on the network segment after
> we had some weird routing issues and had to get that cleaned up. I don't
> know why anyone would do that when there is tons of private IP space.

Excuse 1: "We'll never connect to the internet!"

Excuse 2: "It's only temporary!"

Excuse 3: Typo (At some customers customer I found 192.!168 address which
          where apparently a typo but in use for years so nobody wanted
          to change it.) I also know one company who is using (has
          used?) 2001:8db::/48. I suggested to get v6 PI an properly
          implement IPv6 but never heard from them again.

Excuse 4: "We used the addresses from out training material." - I heard
          this story some time ago: A large German government agency
          wanted to implement IP(v4) and the people attended a course
          about this new TCP/IP stuff at $Vendor. The training material
          was prepared by a student who was using his university's /16 as
          an example. 

BTW: Is the Cisco WLC as default address for DHCP?

| Foelderichstr. 40   | 13595 Berlin, Germany           | +49-151-18721264 |
| | jabber: jenslink at        | ---------------  | 

More information about the NANOG mailing list