Wissensdatenbank

This glossary covers the core networking terminology you'll encounter while managing a VPS — useful as a quick reference when documentation or error messages use unfamiliar terms.

Fundamentals

IP Address — a unique numerical identifier for a device on a network. IPv4 addresses look like 203.0.113.10; IPv6 addresses look like 2001:db8::1.

Subnet / CIDR Notation — a range of IP addresses, written like 203.0.113.0/24, where the number after the slash indicates how many bits are fixed for the network portion.

Gateway — the device (usually a router) that traffic passes through to reach networks outside the local subnet.

DNS (Domain Name System) — translates human-readable domain names into IP addresses.

Ports and Protocols

Port — a numbered endpoint on a device identifying which specific service should handle incoming traffic (e.g. port 80 for HTTP, port 443 for HTTPS, port 22 for SSH).

TCP (Transmission Control Protocol) — a connection-oriented protocol guaranteeing delivery and order, used for most web/application traffic.

UDP (User Datagram Protocol) — a connectionless protocol without delivery guarantees, faster but less reliable; used where speed matters more than guaranteed delivery (DNS queries, some VPN protocols, gaming).

DNS Record Types

A Record — maps a domain to an IPv4 address.

AAAA Record — maps a domain to an IPv6 address.

CNAME Record — maps a domain to another domain name, rather than directly to an IP.

MX Record — specifies the mail server responsible for accepting email for a domain.

PTR Record (Reverse DNS) — maps an IP address back to a domain name, the reverse of an A record.

Security and Access

Firewall — software or hardware that controls which network traffic is allowed to pass, based on defined rules.

NAT (Network Address Translation) — allows multiple devices on a private network to share a single public IP address.

VPN (Virtual Private Network) — creates an encrypted tunnel between two points over an otherwise untrusted network.

Reverse Proxy — a server that sits in front of one or more backend servers, forwarding client requests to them and returning responses.

Forward Proxy — a server that sits in front of clients, making requests to the wider internet on their behalf.

Performance and Reliability

Latency — the delay before data transfer begins, typically measured in milliseconds.

Bandwidth — the maximum rate of data transfer over a connection, typically measured in Mbps or Gbps.

Jitter — variation in latency over time; problematic for real-time applications even when average latency is acceptable.

Packet Loss — data packets that fail to reach their destination, requiring retransmission (for TCP) or simply lost (for UDP).

MTU (Maximum Transmission Unit) — the largest packet size that can be transmitted over a network path without fragmentation.

Load Balancing and Scaling

Load Balancer — distributes incoming traffic across multiple backend servers.

Round-Robin — a load balancing method that distributes requests sequentially across available servers.

Health Check — periodic verification that a backend server is functioning correctly before routing traffic to it.

Advanced/Infrastructure Terms

Anycast — a routing method where the same IP address is announced from multiple locations, and traffic is routed to the nearest one.

CDN (Content Delivery Network) — a distributed network of servers caching content geographically closer to end users.

TTL (Time To Live) — for DNS, how long a record can be cached before requiring a fresh lookup; for packets, the number of hops before a packet is discarded.

Handshake — the initial exchange establishing a connection (TCP handshake) or a secure session (TLS handshake).

Common Diagnostic Tools Referenced Throughout This KB

Continue Reading

• DNS Records Explained: A, AAAA, CNAME, MX, TXT & More
• How to Diagnose and Fix High Network Latency
• How to Monitor Network Traffic with vnStat and iftop

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