Domain
IP generally with IPV4 or IPV6 said,
to make people remember the ip address of each host, obviously unrealistic, so the domain name has a literal meaning on a better solution to this problem, top-level domain, under which may constitute a prefixed a domain name, a domain prefix, the domain can form two, and so on
DNS
DNS (Domain Name System, DNS ), a distributed database as names and IP addresses on the World Wide Web mapped each other, enable the user easier access to the Internet, without having to remember the IP number of strings can be directly read by a machine.
A domain name, the domain corresponding to the finally obtained IP address is called name resolution process (or host name resolution). DNS protocol runs over UDP protocol that uses port 53.
In the document, RFC 2181 RFC have to DNS specification, RFC 2136 DNS dynamic update is explained, RFC 2308 on a reverse DNS lookup cache explained.
DNS resolution process
Enter the domain name query began, if present, is used directly after the ip conversion, if there is an inquiry to the DNS server default settings, if present, then retrieve the data, if not, then the DNS to it the default DNS settings for questioning, iteration until successfully resolved, or the resolution failed.
Since the limit on the number of root servers, in order to solve the efficiency problem, various countries have set up a large number of DNS server mirroring.
MAC address
MAC address (Media Access Control Address), literally translated as media access control address, the address is also known as a local area network (LAN Address), Ethernet address (Ethernet Address) or physical address (Physical Address), which is a device used to confirm the position of line the address of. In the OSI model, the third layer, the network layer is responsible for the IP address, the second layer is the data link layer is responsible for MAC address. MAC address is used to uniquely identify a network card in the network device if one or a plurality of cards, each card will be required and a unique MAC address.
ARP
ARP, i.e., ARP (Address Resolution Protocol), is to obtain a TCP / IP protocol based on the IP address of the physical address.
Host containing the target IP address broadcasts an ARP request to send information to all hosts on the network, and receiving a return message, in order to determine the physical address of the target; the return message after receiving the IP address and physical address is stored in the local ARP cache and retain a certain time, to directly query the ARP cache when the next request to conserve resources. ARP is established, the host on the network can send a self-ARP response message on the basis of mutual trust each host in the network, the other host does not detect the authenticity of the message received when the response message will be credited into the local ARP cache; thus the attacker can send a pseudo host ARP response packet, it sends the information does not reach the expected arrival of the host or the wrong host, which constitutes an ARP spoofing. ARP query command can be used a correspondence relationship the local ARP cache IP addresses and MAC addresses, add or delete a static correspondence relationship. Related agreements have RARP, proxy ARP. NDP used in place of ARP in IPv6.
The same: is the input to a given entity into another entity, DNS domain name convert is IP, ARP and IP sucked into a physical address.
Similarities and Differences: input object does not match the two, and the two different locations in the network hierarchy is located, working in the DNS application layer, the ARP to work in the network layer.
