network dns
A record
Name to IPv4 address. The record people mean when they say the IP for the site.
Knowledge
AllIRacsc-glossaryau-compliancecloudconceptscryptodetectiondnsframeworkshardeningidentityloggingmalwarenetworkpractitionerprivacythreat-intelvulnerability
46 entries
network dns
AAAA record
Name to IPv6 address. Four As. Still forgotten in allow-lists that only list v4.
network hardening acsc-glossary
Air gap
Physically isolated. No cable, no Wi-Fi, no 'just this jump host' to the internet. Removable media is still a path if you let it be.
network dns concepts
Authoritative vs recursive DNS
One holds the zone. The other hunts for an answer and caches it. Mixing them up is how outages get misread.
network detection
BGP
Border Gateway Protocol. How networks exchange routes. A hijack shows up as an unexpected origin ASN or RPKI invalid.
network hardening identity
Bastion host
Jump host. The one box allowed to administer the rest. Harden it like it holds the keys.
detection IR network
Beaconing
Regular callbacks from a host that should be quieter. Interval plus jitter, not a perfect metronome.
malware network acsc-glossary
Botnet
A herd of hijacked devices taking orders. Spam, floods, miners, and stuffing logins all rent the same cattle.
network dns hardening
CAA record
Which certificate authorities may issue for this domain. A DNS policy, not a certificate.
network concepts
CIDR
Classless Inter-Domain Routing. Addresses plus a prefix length. 203.0.113.0/24, not class C.
network dns
CNAME
An alias: this name is that name. People sometimes say "C record"; they mean CNAME. There is no DNS type called a C record.
crypto concepts network
ChaCha20-Poly1305
The other modern AEAD. A stream cipher plus a tag. First-class in TLS 1.3, especially where AES hardware is missing.
detection IR network
Command and control
C2. How the operator talks to a compromised host after they are in. DNS, HTTPS, and traffic that looks like SaaS are common.
network concepts
DHCP
Dynamic Host Configuration Protocol. Addresses and options handed out on the LAN so you do not type them.
network dns concepts
DNS
The internet's name system. Stub asks recursive; recursive walks to authoritative. Analysts live in the query log.
network dns
DNS over HTTPS and DNS over TLS
Encrypt DNS on the path. The resolver still sees the names. DoH can walk around enterprise DNS logging.
network dns detection
DNS spoofing
A fake DNS answer wins. Cache poisoning is the recursive version. Logging and resolver choice matter.
dns detection network
DNS tunnelling
Data moved through DNS queries and answers. Detection is odd volume, long labels, and unusual types.
network dns hardening
DNSSEC
Signatures on DNS data. Authenticity and integrity of answers. Not a VPN. Not HTTPS.
network IR acsc-glossary
Distributed denial of service (DDoS)
Many compromised machines, one target, a flood. Availability dies; the data may still be fine. That is not comfort during checkout.
detection IR network
Exfiltration
Data leaving. Bulk, slow, or stuffed into a protocol nobody is watching. DLP is a control; logs are how you know.
network dns detection
Fast flux
A hostname whose A or NS answers keep rotating. A resilience trick used by some botnets. Short TTL plus churn.
network hardening acsc-glossary
Firewall
A filter on the way in and out, driven by rules. Default allow is a very expensive switch.
network hardening concepts
HTTP Strict Transport Security
A header that tells the browser: this host is HTTPS only, for a while. Preload is a one-way door.
detection network acsc-glossary
Intrusion detection system (IDS)
Watches for unwanted activity and tells someone. Host or network. Alert without an owner is a screensaver.
detection network acsc-glossary
Intrusion prevention system (IPS)
IDS with a fist. Identifies unwanted traffic and can block it in the moment. Mis-tune it and you become the outage.
network dns
MX record
Where mail for this domain should be handed. A hostname and a preference, not an IP in the MX itself.
crypto network identity hardening
Mutual TLS (mTLS)
TLS where both sides present a certificate. The server is not the only one who has to prove who they are.
network dns
NS record
Which nameservers are authoritative for this zone. Delegation lives here.
network detection
NetFlow
Who talked to whom, when, how much. Metadata, not payload. Cheap enough to keep.
network concepts
Network address translation
NAT. Rewrite addresses, and usually ports, at a boundary. Many inside, one outside. Not a firewall policy by itself.
detection network IR
Network detection and response
NDR. Watch the wire or the flow for threat behaviour, not just known signatures. Complements EDR. Does not replace it.
network hardening acsc-glossary
Network segmentation
Cut the network into smaller pieces. Segregation is the rule set between them. Flat is a gift.
network dns
PTR record
Reverse DNS. Address back to a name, under in-addr.arpa or ip6.arpa.
network detection IR
Packet capture
The packets, on disk. Ground truth for a window of time. Heavy, precise, and easy to collect too late.
network identity acsc-glossary
Remote access
Coming in from outside the organisation's network, usually through a gateway. Treat it as privileged even when the user is not.
network dns
SOA record
Start of authority. One per zone. Serial, timers, and who is supposed to be in charge.
network dns
SRV record
Service location: this protocol on this domain lives at that host and port.
identity network acsc-glossary
Spoofing
A message or identity dressed as a trusted source. Email, SMS, caller ID, and websites all do this cheaply.
network dns concepts
TTL
Time to live. How long a resolver may cache this answer. Seconds, not a promise the world forgets on cue.
network dns
TXT record
Free-form text on a name. SPF, DKIM, and DMARC live here. So does a lot of vendor noise.
network concepts crypto acsc-glossary
Transport Layer Security (TLS)
The S in HTTPS. Stops eavesdropping, tampering, and forgery on the wire. TLS 1.3 is the current protocol.
network concepts
VLAN
Virtual LAN. A broadcast domain with a tag. Segmentation only if the rest of the design agrees.
network acsc-glossary
Virtual private network (VPN)
A tunnel plus some discipline. Encryption is common. A full-trust badge on the far side is optional and usually a mistake.
network hardening detection
Web application firewall
WAF. A reverse proxy that tries to stop common web attacks before the app. Rules, not a rewrite of the application.
network identity concepts
Zero trust
Never trust, always verify. A VPN badge is not a day pass. Identity, device, path, and data each get asked again.
Definitions informed by ASD's ACSC glossary. cyber.gov.au glossary