3com 5500-ei pwr Instrução De Instalação

 

1-1 

When configuring DNS, go to these sections for information you are interested in: 

z 

z 

Configuring Domain Name Resolution 

z 

z 

z 

Domain Name System (DNS) is a mechanism used for TCP/IP applications to provide domain 

name-to-IP address translation. With DNS, you can use memorizable and meaningful domain names in 

some applications and let the DNS server resolve it into correct IP addresses. 

There are two types of DNS services, static and dynamic. Each time the DNS server receives a name 

query, it checks its static DNS database before looking up the dynamic DNS database. Reduction of the 

searching time in the dynamic DNS database would increase efficiency. Some frequently used 

addresses can be put in the static DNS database. 

Currently, S5500-EI series Ethernet switches support both static and dynamic DNS clients. 

The static domain name resolution means manually setting up mappings between domain names and 

IP addresses. IP addresses of the corresponding domain names can be found in the static domain 

name resolution table for applications, such as Telnet. 

Dynamic domain name resolution is implemented by querying the DNS server. The resolution 

procedure is as follows: 

1)  A user program sends a name query to the resolver in the DNS client. 

2)  The DNS resolver looks up the local domain name cache for a match. If a match is found, it sends 

the corresponding IP address back. If not, it sends the query to the DNS server. 

3)  The DNS server looks up its DNS database for a match. If no match is found, it sends a query to a 

higher-level DNS server. This process continues until a result, success or failure, is returned. 

4)  The DNS client performs the next operation according to the result.