What DNS record maps a hostname to an IPv4 address?
A record
What DNS record maps a hostname to an IPv6 address?
AAAA record
What DNS record maps an IP address back to a hostname?
PTR record
Which DNS record is used for reverse DNS lookups?
PTR record
Which DNS record identifies the mail server for a domain?
MX record
Which DNS record creates an alias from one domain name to another?
CNAME record
Which DNS record holds arbitrary text like SPF or verification info?
TXT record
Which DNS record identifies the authoritative DNS server for a zone?
NS record
If email servers reject messages due to missing reverse lookup configuration which record is missing?
PTR record
Forward lookup resolves what to what?
Hostname to IP address
Reverse lookup resolves what to what?
IP address to hostname
Which DNS record is required for proper outbound mail server reputation checks?
PTR record
What does NS stand for in NS record?
Name Server
How many bits long is an IPv6 address?
128 bits
How many sections does an IPv6 address normally contain?
8 sections
How many bits per IPv6 section?
16 bits
What characters are valid in IPv6 addresses?
0–9 and A–F
What symbol separates IPv6 sections?
Colon (:)
How many times can double colon (::) appear in an IPv6 address?
Once
What does :: represent in IPv6?
One or more groups of zeros
Are leading zeros required in IPv6 sections?
No
Example of a valid shortened IPv6 address?
FEC2::78CA:0:0:23AB
If an IPv6 address contains letters beyond A–F is it valid?
No
Is this valid IPv6 A82:5B67:7700:AH0A:446A:779F:FFE3:0091?
No (H is invalid)
