Some protocols such as SIP and XMPP require SRV records. SRV records have the form
_service._proto.name TTL class SRV priority weight port target
Example DNS entry with A and SRV record:
host.yourdomain.com 86400 IN A 195.88.229.113
_sipfederationtls._tcp.yourdomain.com 86400 IN SRV 0 5 5061 sip.yourdomain.com. < == (which can be the SIP/SIP-TLS service on host.yourdomain.com) Read more…
DNS servers can be attacked using various techniques including:
One of the simplest ways to defend is to strictly limit zone transfers between nameservers by defining an ACL. Many system administrators allows BIND to transfer zones in bulk outside of their network or organisation. This is an attack vector. You can prevent this by using ACLs: Read more…
named.conf
Create /etc/named.conf file specify the directory location of other files used by DNS: Read more…
A Record
The majority of DNS records are “A” records. A records allow for you to point different sections of your domain to different IP addresses or servers. For example, this would be useful for having “www.domain.com” point to your web server’s IP address and “mail.domain.com” point to your mail server’s IP address. Each record includes a “Host Name” value and a corresponding IP Address. Read more…
Pointer Record (PTR)
Pointer records are the opposite of A and AAAA RRs and are used in Reverse Map zone files to map an IP address (IPv4 or IPv6) to a host name. Read more…
IPv4 IN-ADDR.ARPA Reverse Mapping Domain
We defined the normal domain name structure as a tree starting from the root. We write a normal domain name LEFT to RIGHT but the hierarchical structure is RIGHT to LEFT.
domain name = www.example.com Read more…
highest node in tree is = .com
next (lower) = .example
next (lower) = www
