A C program allowing interogation of a DNS server using the RFC 1035 and RFC 1034 protocols.
The DNS client implemented is a C / C ++ program that works as a resolver DNS, using queries for extract information from DNS servers. The program will receive an argument from the command line as a domain name or IP address and it will display a series of information about it. To obtain the needed information, UDP and TCP are used and messages were constructed in the following structure:
+---------------------+
|
Header
|
+---------------------+
|
Question
|
+---------------------+
|
Answer
|
+---------------------+
|
Authority
|
+---------------------+
|
Additional
|
+---------------------+
-> the question for the name server
-> RRs answering the question
-> RRs pointing toward an authority
-> RRs holding additional information
The client supports the following types of queries:
- A (Host Address)
- MX (Mail Exchange)
- NS (Authoritative Name Server)
- CNAME (the canonical name for an alias)
- SOA (Start Of a zone of Authority)
- TXT (Text strings)
- PTR (Domain Name Pointer)
Example of usage:
./dnsclient google.com A./dnsclient 141.85.37.5 PTR