Glossary
Short explanations for common network terms.
ASN (Autonomous System Number)
A numeric identifier for a network on the internet, usually an ISP or large organization.
Why it matters: Helps trace routing and ownership of an IP range.
Common misunderstanding: Not a unique company ID; one organization can operate multiple ASNs.
Example: AS13335 (Cloudflare).
ISP (Internet Service Provider)
The company providing network access for an IP address.
Why it matters: ISP type can affect latency, reputation, and access policies.
Common misunderstanding: The ISP is not always the end user; it can be a reseller or carrier.
Example: AT&T, Orange, Vodafone.
Organization
The entity that owns or manages the IP block.
Why it matters: Indicates who controls the network and the likely use case.
Common misunderstanding: Organization may differ from the ISP or actual user.
Example: A university or cloud provider.
Reverse DNS
A hostname mapped to an IP address via PTR records.
Why it matters: Used to validate mail servers and identify services.
Common misunderstanding: Reverse DNS does not prove ownership or identity.
Example: 1.0.0.127.in-addr.arpa -> localhost.
CAA (Certificate Authority Authorization)
A DNS record that specifies which certificate authorities may issue TLS certificates for a domain.
Why it matters: Helps prevent unauthorized certificate issuance.
Common misunderstanding: CAA does not encrypt traffic; it only restricts issuance.
Example: CAA 0 issue "letsencrypt.org".
CDN (Content Delivery Network)
A distributed network that caches and serves content closer to users.
Why it matters: Can change apparent IP location and performance.
Common misunderstanding: CDN IPs do not necessarily reveal the origin server.
Example: Cloudflare or Fastly edge nodes.
Tor Exit Node
A public exit point for the Tor anonymity network.
Why it matters: Often flagged by services due to abuse risk.
Common misunderstanding: A Tor exit does not identify the user; it hides them.
Example: An IP used by Tor to reach public sites.
VPN (Virtual Private Network)
A tunnel that routes traffic through another network.
Why it matters: Can mask location and change IP reputation.
Common misunderstanding: VPNs do not guarantee anonymity or security by themselves.
Example: Corporate VPN gateway.
Proxy
An intermediary server that forwards traffic on behalf of a client.
Why it matters: Proxies can alter IP reputation and access rules.
Common misunderstanding: Not all proxies are anonymous; many add headers.
Example: A forward proxy used by a company.
CGNAT
Carrier-grade NAT that shares a public IP among many users.
Why it matters: Can cause shared reputation and port limitations.
Common misunderstanding: CGNAT does not mean a VPN or proxy is used.
Example: Mobile networks often use CGNAT.
IPv4
The older 32-bit internet protocol address format.
Why it matters: Still widely used but increasingly scarce.
Common misunderstanding: IPv4 is not inherently less secure; it is just older.
Example: 8.8.8.8.
IPv6
The newer 128-bit internet protocol address format.
Why it matters: Provides more addresses and can change routing.
Common misunderstanding: IPv6 is not always enabled even if supported.
Example: 2001:4860:4860::8888.
RTT / Latency
The round-trip time for a packet to travel to a destination and back.
Why it matters: High RTT affects responsiveness and timeouts.
Common misunderstanding: Low RTT does not guarantee high bandwidth.
Example: 20 ms to a nearby server.
Packet Loss
The percentage of packets that fail to reach their destination.
Why it matters: Even small loss can break real-time traffic.
Common misunderstanding: Loss is not always due to distance; congestion can cause it.
Example: 2% loss on a busy Wi-Fi.
Hosting / Datacenter
IPs from cloud or datacenter providers rather than consumer ISPs.
Why it matters: Often treated differently by risk systems and rate limits.
Common misunderstanding: Datacenter IPs are not always bad; they are just categorized.
Example: AWS, Google Cloud, Azure.
Residential IP
An IP assigned to consumer broadband or mobile users.
Why it matters: Typically trusted more for everyday access patterns.
Common misunderstanding: Residential IPs can still be shared or proxied.
Example: Home fiber connection.