AS21965Highmark Inc
United StatesRegistryARINAs of 29th September 2026, AS21965 (Highmark Inc), a network registered in the United States with ARIN, originates 22 IPv4 prefixes covering 5.6k addresses. By IPv4 address space that makes it the 14,740th-largest of the 79,607 networks we see originating IPv4, and the 4,204th-largest of 18,442 in the United States. It is seen behind 6 upstream networks, most often AS6461 (Zayo Bandwidth) and AS3356 (Lumen (Level 3)), and in front of 1 downstream network. None of its announcements have a valid RPKI ROA. 100% of its routes reach at least 90% of full-feed peers.
At a glance
IPv4 prefixes
IPv6 prefixes
IPv4 addresses
IPv6 /64s
Upstream graph
The networks AS21965 is seen behind, one and two hops out, drawn from real AS paths.
Networks observed one and two hops upstream of AS21965 in real AS paths. A thicker line means more vantage points saw that adjacency, so weight tracks how well attested it is — not how much traffic it carries. Adjacency is an observation; whether it is a transit purchase or a settlement-free peering is an inference, and is labelled as one wherever we show it.
Neighbouring networks
14
adjacent networks
- Upstreams
- 643%
- Peers
- 750%
- Downstreams
- 17%
Networks carrying this one's traffic toward the rest of the internet.
| Network | Country | Relationship | Paths | Vantage pts |
|---|---|---|---|---|
| AS6461Zayo Bandwidth | US | Peer | 1,334 | 82 |
| AS3356Lumen (Level 3) | US | Peer | 1,134 | 81 |
| AS15830Equinix, Inc. |  NL | Peer | 580 | 82 |
| AS7018AT&T Enterprises, LLC | US | Peer | 149 | 9 |
| AS46887Zayo (fka. Crown Castle) | US | Peer | 50 | 50 |
| AS7016Comcast Cable Communications, LLC | US | Peer | 32 | 32 |
Prefixes
The largest blocks AS21965 originates, widest first.
| Prefix | Addresses | Visibility |
|---|---|---|
| 157.154.3.0/24 | 256 | 82/82 |
| 157.154.4.0/24 | 256 | 82/82 |
| 157.154.5.0/24 | 256 | 82/82 |
| 157.154.6.0/24 | 256 | 82/82 |
| 157.154.7.0/24 | 256 | 82/82 |
| 157.154.8.0/24 | 256 | 82/82 |
| 157.154.11.0/24 | 256 | 82/82 |
| 157.154.14.0/24 | 256 | 82/82 |
| 157.154.20.0/24 | 256 | 82/82 |
| 167.164.3.0/24 | 256 | 82/82 |
Routing health
How AS21965's own announcements validate against RPKI and how far they propagate. The same measures for the whole routing table are on the routing table in numbers.
RPKI origin validation
- Valid0.0%0
- Invalid0.0%0
- No ROA100.0%22
Propagation
- Globally propagated90% of full-feed peers or more100.0%22
- Partially propagated40% to 90%0.0%0
- Seen by few peersUnder 40%0.0%0
Prefix sizes
IPv4 — 22 prefixes
Recent changes
Announcements that started or stopped since 30th Aug 2026.
No announcement by AS21965 started or stopped in this period.
Routing data derived from RouteViews MRT archives, BGPKIT relationship inference and public registry data.