Panasonic UF-9000 Service Manual

Contents

232UF-9000JAN 2004Ver. 1.0DP-180/1909.5. Upper Layer9.5.1. DNS (Domain Name System)The DNS (Domain Name System) protocol provides host name and IP address resolution as a service toclient applications. DNS servers enable humans to use logical node names, utilizing a fully qualified domainname structure, to access network resources.Domain Names are comprised of 2 or more parts, separated by dots. The part on the left is the mostspecific, and the part on the right is the most general. A given device may have more than one DomainName but a given Domain Name points to only one device. For example, the Domain Names below:Panasonic.comMail.panasonic.comifax.panasonic.comcan all refer to the same device, but each domain name can refer to no more than one device.Usually, all of the devices on a given network will have the same right-hand portion of their Domain Names(i.e. panasonic.com in the examples above). It is also possible for a Domain Name to exist but not beconnected to an actual device.This is often done so that a group or business can have an Internet email address without having toestablish a real Internet site. In these cases, some real Internet machine must handle the email on behalf ofthe listed Domain Name.Specification for this name system follows this basic guideline.• The name must be separated by dots and must start with ASCII code.• Only Alpha numeric and hyphen are available.• Up to 63 characters maximum, separated by dots.• Up to 255 characters maximum, including all dots.• Capital letters and small letters are not identical. (Case Sensitive.)The advantage of using a DNS server over a host lookup table, for host name resolution, is to avoid theneed for a single centralized clearinghouse for all names. The authority for this information can bedelegated to different organizations on the network responsible for it.There are at least 10 Root DNS servers installed all over the world.DNS Server (root)DNS Server(panasonic.com)DNS Server (jp)DNS Server (co.jp)DNS Server(panafax.co.jp) Mail Server mlsv.panafax.co.jpdomain123456 78910DNS Name Resolution SamplePanasonicDevice