Home| NetSize | Search

AS#: List Type:


What is an AS:

An AS is a collection of IP subnets that are hosted under one or more network operator that are defined under a common routing policy. You can find more info about AS on wikipedia.

Go to top


We are quite accurate, but we won't go as far as to say we are perfect. Most of the results featured on this website are cached from days previous to lower the number of hits against our source for the data, as well as to increase the speed of the site. We can go up to being 90 days without refreshing the cache, though it is usually sooner then that. This may change at any time if we experince issues with our source of data.

Though we claim to be very accurate, we get all our data from a third party site, and though we wish to guarantee the data, we simply can't. This means that even though we try our best, some data can be completely wrong and be completely off. This could be because of a network operator being abusive, or that a hiccup occurred at the time of checking the data.

Go to top

Proper Usage:

Proper usage of the ASN ban list is very very very important. Using it wrong can end up blocking a whole customer base in no time flat. When you are blocking an ASN you are not only blocking bad people, but all good people in that network as well. So honestly, we will tell you right now that 9 out of 10 times, using the lists created will be not only bad, but wrong! Make sure you also don't block your own ASN as you may block yourself from your server, and the only way to get back in will be another system, or your provider. As such you have been warned, be careful!
A good example of how to use our ASN blocklist is in an email enviornment. You could have two servers, one with a high priority and another with a low priority. Your high priority server would be the master server, and you would have some spam protection, but nothing massive or heavy. Now for bad ASNs that have a lot of spam you would apply our list to the master server. This would force the email servers to use your secondary server which would relay mail to your main server. On this secondary server you would have a ton of extra protection to make sure that no spam gets by. Why do you need the secondary server? Simple, if you don't any good/legit mail from that bad ASN will never get to your users. As always, blocking an ASN is blocking not only bad traffic, but good traffic as well and as of current there is no 100% bad ASN.
Another good option is when you legally have to block a country. For example, you could block all traffic from Iran if you found out there ASNs and grabbed each list from here. Though this doesn't fool proof your setup, it will help with a good chunk of it. Please remember that no matter what you do, if there is a will, there is a way.
A bad example would be, applying the ASN to your server for "extra protection". If you do not have any direct reason to block an ASN then don't. You will most likely cause more issues then anything else. Another bad one is spam prevention.

Go to top


All of our lists can be downloaded via our API function allowing you to quickly implement them in your scripts, or via a cronjob. To do this simply add "&api=1" to the end of the URL of your preferred list. It will automatically export our list with no extra bells or whistles. We kindly ask you not to abuse it however. An example URL is: ./index.php?asn=1&type=iplist&api=1.
You can also export our data via JSON. Example data can be found here. The array is built as follows: "asn" will state the ASN you are getting the info for. "time" will state when we last updated our cache. "ips" is an array in itself that will have all ips for that ASN listed in it. Please note that this is both IPv6 and IPv4.

Go to top


As stated before we provide no warranty at all! Use at your own risk. You are liable for your own actions. Simply put, think before doing, as we will not remote into your server and fix the problem you made for yourself. Nor will we be financially accountable for your actions. If you however really wish to ask for help, we will try and give you some good advice on our project listing.

Go to top

Commercial Usage:

You can use our lists in commercial use, but we ask for some compensation(donation) or to not charge them(your clients) at all for our service. We also require that you make note somewhere visible that the data came from us. We however, even with a donation, will not provider commercial support, though you still may ask, but as everything we hold the right to refuse your request with no justification. This also applies for non-profits, schools, and any other organization. If you have still further questions, it would be best to go to our project listing.

Go to top


This app was made by Cameron Munroe in request for a more dynamic build of our initial build, which can be found here . We initially built it in response to this forum thread which then spawned this thread. I thank all that helped in the creation of this service such as Dr.Mike, Francisco, DomainBop, and anyone else I failed to mention.

Go to top

Information Source:

We used to use for our data, however we have changed to the lovely system. It is faster, and is more accureate then our previous system!

We get our information about which IPs are hosted by which AS from We use an in house PHP app to pull out all the vital information from there site and rebuild it nicely here for your convenience.

Go to top