Network Services Flashcards
What does DNS use to partition the domain landscape?
Zone files
Zone files contain what? Give example
Resource records like A records and MX records.
What is the IPv6 equivalent of A-resource records?
AAAA record
What do TXT records allow?
To add arbitrary information relating to the DNS in text form and for this to be queries. An example would be showing proof of ownership for a domain name by way of adding the name of the business or person and their address details to the TXT record.
How does Sender Policy Framework record work
It tells the internet which email servers a domain uses to send mail. When mail is received at another domain, it will check the SPF record and compare the sending email servers, if they don’t match the mail will be rejected.
What is DKIM and what does it enable?
Domain Key’s Identified Mail. Similar to SPF, it allows for authentication of email messages but it uses a cryptographic key stored in the TXT record.
What are SRV records used for?
Service (SRV) locator records are used for locating services such as LDAP or SIP
What type of DNS record assists mail servers in identifying the mail server for your domain?
MX record
*if you want to receive mail from other domains, you need this record set
What must you publish if you want to receive mail from other mail servers?
an MX record
If you wanted a host to have more than one FQDN, how would you accomplish this?
By using a CNAME record to specify the alternative FQDN name and map it to the FQDN in the A record
What type of record maps an IP to an FQDN?
PTR (Pointer Records)
*this is known as a reverse lookup
Which type of DNS record contains all the servers responsible for a particular zone file?
NS record (Name Server). note - you can't perform a zone transfer without them
what does the SOA record do?
The Start Of Authority record defines parameters in the zone file like what is the primary DNS server, the TTL and refresh intervals to update secondary DNS servers
What is the split-brain DNS model?
Whereby DNS is split so that one DNS handles internet/public host resolution and another is based internally to manage private host name resolution.
What is the risk of using a public DNS to resolve hosts on a private network?
If the same DNS was used to resolve both external and internal, a hacker would be able to find out internal names easily.