'Application' Layer Network Protocols Flashcards
What is a SOA DNS record used for?
The ‘start of authority’ (SOA) record stores important information about a domain or zone such as the email address of the administrator, when the domain was last updated, and how long the server should wait between refreshes.
What is an MX DNS record used for?
The MX record indicates how email messages should be routed in accordance with the Simple Mail Transfer Protocol (SMTP, the standard protocol for all email). Like CNAME records, an MX record must always point to another domain.
Resource records are the basic information element of the Domain Name System (DNS). An MX record is one of these, and a domain may have one or more of these set up, as below:
Domain TTL Class Type Priority Host
example. com. 1936 IN MX 10 onemail.example.com.
example. com. 1936 IN MX 20 twomail.example.com.
What is a TXT DNS record used for?
TXT records are a type of Domain Name System (DNS) record that contains text information for sources outside of your domain.
Basically used for any old thing, but commonly used to ensure email security:
- Sender Policy Framework (SPF) records protect your domain from being used to send spam.
- Domain Keys Identified Mail (DKIM) signing uses encryption to secure the content of your email.
- Domain-based Message Authentication, Reporting, and Conformance (DMARC) authentication gives you control over SPF and DKIM policies.
- MTA-STS increases security for SMTP connections when both sending and receiving servers use this standard.
What is an A record used for?
it indicates the IP address of a given domain
What is an NS DNS record for?
NS stands for ‘nameserver,’ and the nameserver record indicates which DNS server is authoritative for that domain (i.e. which server contains the actual DNS records). A nameserver is a type of DNS server. It is the server that stores all DNS records for a domain, including A records, MX records, or CNAME records.
What is a PTR DNS record used for?
Used for a “reverse DNS lookup.”
A DNS pointer record (PTR for short) provides the domain name associated with an IP address, as opposed to an A record, that provides the IP address associated with a domain name,
What is a HINFO record?
A HINFO-record specifies the host / server’s type of CPU and operating system. This information can be used by application protocols such as FTP, which use special procedures when communicating with computers of a known CPU and operating system type.
What is a CNAME record?
A Canonical Name record (abbreviated as CNAME record) is a type of resource record in the Domain Name System (DNS) that maps one domain name (an alias) to another.
One can, for example, point ftp.example.com and www.example.com (as CNAME records) to the DNS entry for example.com, which in turn has an A record which points to the IP address. Then, if the IP address ever changes, one only has to record the change in one place within the network: in the DNS A record for example.com.
CNAME records must always point to another domain name, never directly to an IP address.
What is TKIP?
TKIP is a suite of algorithms that works as a “wrapper” to WEP, which allows users of legacy WLAN equipment to upgrade to TKIP without replacing hardware.
First, TKIP implements a key mixing function that combines the secret root key with the initialization vector before passing it to the RC4 cipher initialization. Second, TKIP/WPA implements a sequence counter to protect against replay attacks. Packets received out of order will be rejected by the access point. Finally, TKIP implements a 64-bit Message Integrity Check (MIC) and re-initializes the sequence number each time when a new key (Temporal Key) is used.
What do EAP, LEAP and PEAP stand for?
Lightweight/Protected Extensible Authentication Protocol
What does EAP-TLS, EAP-TTLS, and EAP-FAST stand for?
Transport Layer Security - client certificate
Tunneled Transport Layer Security - client credentials, server certificate
exible Authentication via Secure Tunneling - new version of LEAP
