CIDR Range

123.51.24.0/21

2.0K IPs /21 Symbio Networks AS38333 Australia APNIC

Addresses

2,048

2.0K

IP Range

123.51.24.0

→ 123.51.31.255

Sub-ranges

within this block

PTR Density

97.7%

2.0K of 2.0K IPs have PTR

Reputation · trust score

A transparent 0–100 signal. Every entity starts at a neutral baseline of 65; threat-intel blocklists, exposure, reverse-DNS, routing and allocation each adjust it up or down. Higher is more trustworthy.

80/100

Trusted

How this score is built

Baseline (neutral) 65
Long-established allocation (20y) +6
Has a reverse-DNS (PTR) record +5
Enterprise allocation +4
Trust score 80 / 100

Experimental · trust-vectors model v1.3.0 — a transparent heuristic, not a definitive verdict. How it works →

Geolocation

First and last addresses in 123.51.24.0/21

123.51.24.0/21 runs from 123.51.24.0 to 123.51.31.255.

First 16

123.51.24.0 123.51.24.1 123.51.24.2 123.51.24.3 123.51.24.4 123.51.24.5 123.51.24.6 123.51.24.7 123.51.24.8 123.51.24.9 123.51.24.10 123.51.24.11 123.51.24.12 123.51.24.13 123.51.24.14 123.51.24.15

Last 16

123.51.31.240 123.51.31.241 123.51.31.242 123.51.31.243 123.51.31.244 123.51.31.245 123.51.31.246 123.51.31.247 123.51.31.248 123.51.31.249 123.51.31.250 123.51.31.251 123.51.31.252 123.51.31.253 123.51.31.254 123.51.31.255

BGP Routing

Live BGP anomalies →

Not announced as an exact prefix — covered by the announced supernet 123.51.0.0/17.

Announced prefix

123.51.0.0/17

Origin AS

AS38333

Announcement samples

81,337

Last seen

2026-11-13 13:37:32

Frequently Asked Questions

What is 123.51.24.0/21?

123.51.24.0/21 is a CIDR network block containing 2,048 IPv4 addresses (from 123.51.24.0 to 123.51.31.255). CIDR notation combines an IP address with a prefix length to define a range of addresses.

Who owns the 123.51.24.0/21 network?

The 123.51.24.0/21 range is allocated to Symbio Networks and announced via AS38333 from Australia.

Last updated: 2026-11-13 14:09:05 UTC