Can anyone inform me what does it mean in DNS zone file $ and @
There are 3 directives starting with the "$" ($ORIGIN, $INCLUDE and $TTL)
@ is the same as $ORIGIN. Take a look here
Also let me know what my website is opening with URL: hxxp://www.example.com but not opening with hxxp://example.com
Is it DNS issue or apache serveraliases issue?
If both example.com and www.example.com
resolve to the same IP address, then it's an apache ServerAlias issue.