Problems with newish IP block assignment issues from ARIN

Eric Kuhnke eric.kuhnke at
Mon Feb 8 20:30:41 UTC 2021

One common cause of this issue is entities out there that have very old
'bogons' filters in place for the larger block, as an entire /8, /12 to /16
size of space that, many years ago, was unallocated space. Without getting
the end point organizations running the httpd, firewalls or whatever to fix
their broken configuration, it's a hard issue to fix from your end.

On a longer term time scale like multiple years, the reachability of an IP
block like yours will gradually increase as people with broken services are
contacted by additional persons to say "hey, this really is valid ARIN IP

On Mon, Feb 8, 2021 at 12:15 PM Justin Wilson (Lists) <lists at>

> Folks,
> Have a gremlin we have been chasing around for several months now and it’s
> becoming a major issue as we are getting tighter on IPV4 and needing to
> give some provider assigned space back.
> In June we received a /22 from ARIN.  As is my workflow I started
> announcing it but waited a month while I checked out the geolocation
> databases for correct info, did testing ,etc. All this time our test
> accounts could browse web-sites, etc.
> We put one of the pools into production and things ran good for awhile.
> Then we started getting the occasional web-site was not working.  After
> several of these we started assigning the customer an IP out of one of our
> other ARIN blocks and the web-site would be fine and reachable. The issue
> seems to reside just on this /22.  We have other blocks from ARIN and they
> are just fine.  We can assign an IP out of this new block and can’t reach
> certain web-sites.  We turn around and assign out of another block and
> web-site works just fine.
> We have two upstreams and an IX on this network.  We have tried
> withdrawing the route on this particular /22 and isolating to one upstream
> alone and the problems still persist.
> Many of the web-sites in question are government (both state and local),
> online universities, and the occasional local news station.  They are
> diverse enough to not be traced down to a common point, except the IP
> block.
> We announce the IP block via BGP the same exact way we announce the other
> blocks. Traceroutes show the path going the same way no matter what IP
> block the customer has.
> It acts like the IP block was blacklisted at some point and got on some
> bad lists but I don’t want ti limit myself to that theory.  I have opened
> up a ticket with ARIN asking for any guidance.  Has anyone ran into this
> with new space assigned? Any tools, sites, etc. I can use to do further
> troubleshooting.  The IP block does not appear to have any blacklisted IPs
> according to MX toolbox, and some others.
> The block in question is  It has been RPKI certified and
> has IRR entries.
> Thanks in advance
> Justin Wilson
> j2sw at
>> - All things jsw (AS209109)
> - Podcast and Blog
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