The upstreams had a valid route back to it, it just didnt have a valid forward route - and thank goodness because the traceroute boxes got ddosed into oblivion.
This was a trick which ONLY used 1 ip address and some borrowed PTRs. I could have used used space too, but the customers mail probably would have stopped working.
The source of the IP block is an ISP that gets a /20 at a time. Its a fact of life that unused blocks do sit around.
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The upstreams had a valid route back to it, it just didnt have a valid forward route - and thank goodness because the traceroute boxes got ddosed into oblivion. This was a trick which ONLY used 1 ip address and some borrowed PTRs. I could have used used space too, but the customers mail probably would have stopped working. The source of the IP block is an ISP that gets a /20 at a time. Its a fact of life that unused blocks do sit around.