Help on setting up a new block

Odd Issues

We recently went through an IP Broker and bought a /18 worth of IP’s

I am listing all my information below. Should be public record.

AS Number/Range 395437
AS Handle AS395437
RPKI Certified Yes

As for the IP Block

Net Range -
Net Name HCL-73
Net Handle NET-138-43-128-0-1
Net Type Direct Allocation
Parent NET-138-0-0-0-0 (VR-ARIN)
RPKI Certified Yes

In addition, I believe I got all the information in the IRR. I am unclear on this part, but I do know ATT is happy now. I can pass traffic through their network.

whois -h " --roa 395437"

0 - Valid

Do a search on the /16 parent block. It has a history of being on block lists. I imagine some admins have old lists that they do not update very often, or have the entire /16 or greater blocked. I also went through this process when we purchased IPs, and I’ve had to contact hundreds of networks over the last couple of years to try and get our blocks removed from their firewalls. Our specific block was never on any block lists, but the parent was plastered all over the place.

It’s potentially more difficult now than in the past because there are some hosting providers that are simply a few people that own VMs on some other infrastructure that they do not control or have visibility into. The VM hosting company might be blocking your network, and so the VMs never see your traffic. This means you might contact Landstar, and then Landstar calls up their web person, but the web person doesn’t understand this stuff. The web person phones his web hosting company who can’t find anything wrong, because they never see your packets to begin with. Now the web hosting company (if you can get them to do this) needs to contact their DC company that is hosting their VMs to find out if there is a firewall or anti DDoS system etc that is sitting in front of their VMs.

Most of these calls take a long time. There is a lot of hand-holding, and captures that need to be sent, and then you just hope you can find someone willing to dig into it on the other end of the phone.

Good luck with the process. I believe you will be successful in most cases, but it will take awhile.

Taking a quick look, seems like reachability to the first /24 at least is ok, so I don’t think you have a problem there.

You may have picked up a subnet with some nuggets of abuse history in there, it’s quite common on the secondary V4 market.

I would start with basic stuff first.

Traceroutes to check if/where the packets are being dropped. If the path is clear, then it’s probably a HTTP level block, in which case figure out if these companies share the same CDN/web protection solution/hoster. If that’s the case, contact them directly.

Filip Hruska

I found an interesting pattern. I see a lot of traffic stopping at Big datacenter? Could they be doing some blocking?


Could be. They were acquired by IBM a few years ago.

They block IP address from Iran, Cuba, North Korea, and Syria.

You can check for more details.

of course at the end of the day, there is ZERO requirement for anyone to accept traffic from any prefix. to paraphrase an old greybeard,
“my network, my rulez”


of course at the end of the day, there is ZERO requirement for anyone to
accept traffic from any prefix. to paraphrase an old greybeard,
"my network, my rulez"

Wouldn't this be in conflict with the idea of "network neutrality" rules?



Have we reached the point where it is (or should be) due diligence and a BCP to
make sure your new address space is reachable on IPv6 as well, to improve your
chances of being reachable even if your IPv4 space is in somebody's block list?

Depends. Was softlayer up-front with the customers about what addresses
are blocked, and why?

If the customers knew that softlayer had a block list and had a way to tell
if it was impacting their network access, that's one thing.

If softlayer was doing it without informed consent from its customers, that's
a different kettle of fish....

not clear what network neutrality has to say about this. are you required to accept DDoS traffic or is that covered by net neutrality?


Hi John,

I have gone through this pain previously and I suggest you contact the main Geo IP database providers and have them update their DB as some organisation use them, they don’t rely on IRR entries.
Some hosting companies and content/streaming/Pay-TV providers also use these GeoIP Databases which may take a while to update.

Here are a some of these companies FYI;

W3C Geolocation
Geo IP by MaxMind