Understanding results of nslookup

Question

Where can I find a definition for the X-Forwarded-For HTTP header? Most sites refer to the Wikipedia site. Here the X-Forwarded-For format is described as X-Forwarded-For: client, proxy1, proxy2. I'm curious what valid strings for one entry can be. Are following examples valid entries?

• 192.0.2.60
• 192.0.2.60:58074
• 2001:db8:cafe::17
• [2001:db8:cafe::17]:47011
• "[2001:db8:cafe::17]:47011"

Solution

The Hash, and number after is the default TCP/UDP name server port.

Any answer that originates from the DNS Server which has the complete zone file information available for the domain is said to be Authoritative answer.

When the DNS servers maintains a cache file for the results of all queries performed in the past, and received an authoritative response, when a DNS query is asked for, it searches the cache file, and return the information available as Non-Authoritative Answer.