Networking
18 sheets
- digdig queries DNS servers and prints the full answer. Use it to check records, test a specific resolver, follow delegation from the root and see whether a zone…
- DNS EncryptionEver since DNS was created in 1987, it has been largely unencrypted. Everyone between your device and the resolver is able to snoop on or even modify your DNS…
- DNS over HTTPS (DoH)DoH sends DNS queries inside HTTPS (TLS (Transport Layer Security)) on TCP port 443, as defined in RFC 8484. It looks like normal web traffic. Compare with DNS…
- DNS over TLS (DoT)DoT wraps standard DNS queries in a TLS (TLS (Transport Layer Security)) session on TCP port 853, so queries cannot be read or tampered with on the path…
- DNS Record TypesDNSSEC signing and validation: DNSSEC. On Windows use Resolve-DnsName example.com -Type MX (see Windows DNS Server). Encrypted lookups are covered in DNS…
- DNSSECDNSSEC signs DNS data so a validating resolver can prove an answer is genuine and unmodified. This sheet covers signing a zone with BIND (dnssec-policy with…
- Generate a DKIM KeypairDKIM signs outgoing mail with a private key. The public key is published in DNS as a TXT record so receivers can verify it. We use OpenSSL to generate the…
- Mail Server DNS Records Cheat-SheetIf you want to run a mail server on the public internet, you need to set up your DNS records correctly. While some DNS Records (DNS Record Types) are necessary…
- Mesh VPN ComparisonA mesh VPN connects devices directly to each other (with a relay as fallback) instead of through one central gateway. This sheet compares the common options…
- mTLS (Mutual TLS)In ordinary TLS only the server proves its identity. With mutual TLS the client also presents a certificate, and the server checks it against a CA it trusts…
- Ports and ProtocolsA reference of well-known TCP/UDP ports, the services and homelab/DevOps tools that use them, IP protocol numbers, private and special address ranges, and the…
- SMTPSimple Mail Transfer Protocol moves email between servers and from clients to servers. Related: Mail Server DNS Records Cheat-Sheet, Generate a DKIM Keypair…
- socat and netcatnc (netcat) opens simple TCP or UDP connections and listeners; socat relays data between almost any two endpoints (TCP, UDP, UNIX sockets, files, TLS…
- TCP vs UDPThe two main transport-layer protocols. TCP gives reliable ordered delivery, UDP gives fast best-effort datagrams.
- TLS (Transport Layer Security)TLS encrypts and authenticates traffic between two parties. It is the successor to SSL, which is deprecated and must not be used. HTTPS is HTTP over TLS.
- TLS HandshakeIn a TLS/SSL handshake, clients and servers exchange SSL certificates, cipher suite requirements, and randomly generated data for creating session keys.
- Twisted Pair Cables Cheat-SheetAs the title states, a UTP cable has no shielding. This is the most used and most basic type of cable. The cable contains pairs of wires twisted together to…
- VPN (Virtual Private Network)A VPN creates an encrypted tunnel between devices or networks so traffic can cross an untrusted network safely.