INFO Flashcards
is a command that queries the Domain Name System servers for resource records.
- Can be used on Windows and Linux OS’s
Nslookup
allows a user to execute queries back-to-back without typing the entire command for each query
Interactive mode
involves typing the entire command for each query. With a known domain name, nslookup will enumerate all IP’s correlated to that IP, aka DNS query.
Non-interactive mode
There is a browser based version of nslookup as well
nslookup.io
nslookup www.<domain>.com</domain>
Example: nslookup www.virustotal.com
syntax (Nslookup)
When you just type in “___________” into your terminal you will enter the interactive mode
nslookup
nslookup: this simply Translates an IP address into DNS
“ reverse nslookup” or a “reverse DNS”
Example: nslookup 8.8.8.8 (google)
nslookup: This provides mail exchange records
nslookup -query=MX microsoft.com
nslookup: This provides start of authority records
nslookup -query=SOA microsoft.com
nslookup: This provides name server records
nslookup -query=NS microsoft.com
nslookup: This provides all related records
nslookup -query=any microsoft.com
True or False
When conducting a Reverse DNS lookup nslookup command, it would look like nslookup www.google.com
False
What nslookup command provides mail server information?
-query=MX
is a command that queries the Domain Name System servers for records relating to IP addresses, mail exchanges, and name servers
Dig
The results from queries can be utilized to troubleshoot network issues.
The dig command resolves names through the resolver libraries that are located on the OS.
Dig
When a DNS query is made, information is gathered from the DNS server indicated.
If the indicated server is not found then it will go through the list below until it identifies a source to query:
- Specified DNS server
- OS’s default resolver (I.e. resolv.conf)
- Local host
more options, and more verbose answers
dig <dns> <type></type></dns>
Example: dig virustotal.com
Syntax
Dig Query Types:
ANY = All Pertinent Records
A = IPV4 Records
AAAA = IPv6 Records
CNAME = Canonical Name Records
MX = Mail Exchange Records
SOA = Start of Authority Records
NS = Name Server Records
PTR = pointer resource record
The results above indicate the following:
- Version of utility installed: 9.11.3-1
- Header indicates 1 query was made and 0 errors (NOERROR) occurred; and “id” indicates this query’s identification #.
- The DNS server replied with the results within “ANSWER SECTION,” which includes google.com.’s IPV4 address (indicated by “A” and the IPV)
- “184” indicates the time to live (TTL) and “IN” represents internet class query
- Multiple IP’s may represent a load balancer
Dig Query Mod: This example provides Mail Exchange Server Record Types:
Example: $ dig microsoft.com MX
Query Mod: This example provides IPV4 Record Types:
Example: $ dig microsoft.com A
Dig Query Mod: This example provides Name Server Record Types
Example: $ dig microsoft.com NS
Query Mod: This example provides Start of Authority Record Types:
Example: $ dig microsoft.com SOA
Query Mod: This example provides IPV6 Record Types:
Example: $ dig microsoft.com AAAA
Query Mod: This example provides ALL Record Types:
Example: $ dig microsoft.com ANY