Network Overview
| ASN | AS104 |
| Organization | University of Colorado at Boulder |
| Announced IPv4 ranges | 13 |
| Total IPv4 addresses | 91,136 |
Sample IP Ranges Announced by AS104
| Range Start | Range End | Lookup |
|---|---|---|
128.138.0.0 |
128.138.255.255 |
Details → |
129.19.192.0 |
129.19.255.255 |
Details → |
146.5.20.0 |
146.5.23.255 |
Details → |
192.12.238.0 |
192.12.238.255 |
Details → |
192.12.240.0 |
192.12.242.255 |
Details → |
192.12.244.0 |
192.12.245.255 |
Details → |
What Is an Autonomous System?
An autonomous system (AS) is a collection of IP networks operated by a single organization - an ISP, cloud provider, enterprise, or university - that shares a common routing policy. Each AS is identified by a unique AS number (ASN) and exchanges routing information with other systems using the BGP protocol.
Knowing which ASN an IP belongs to reveals who actually operates the network behind it - useful for fraud analysis, traffic quality assessment, and abuse investigation. Use the IP lookup tool to find the ASN for any address.
Frequently Asked Questions
What is AS104?
AS104 is the autonomous system operated by University of Colorado at Boulder, announcing 13 IPv4 ranges (91,136 addresses).
Who operates AS104?
University of Colorado at Boulder. An autonomous system is a network under a single administrative entity that exchanges routes with other networks via BGP.
How do I check if an IP belongs to AS104?
Enter the IP into our free IP lookup - the result shows the ASN, operator, geolocation, and VPN/datacenter flags.