BinTec X4000, Руководство пользователя

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X4000 User’s Guide 247
Basic IP Settings
8
In practice, the DNS of the Internet Service Provider is often used for name
resolution.
Advantages of Name Resolution with X4000
X4000 has the following functions and facilities for name resolution (port 53):
■
DNS Proxy, for passing DNS requests to the right DNS.
■
DNS cache, for saving the results of DNS requests.
■
Static name entries, for defining assignments of names to IP addresses.
■
Filter function, to prevent the resolution of certain names.
■
Monitoring via Setup Tool, to provide an overview of DNS requests in
X4000 .
This is how it works:
DNS Proxy DNS Proxy makes the tedious updating of HOSTS files on PCs in the LAN
unnecessary, as you can enter X4000 as DNS on the relevant PCs. DNS
requests are passed by the PC to X4000 for processing. The configuration of
the PCs in the LAN is then easy and can also be left at provider changes. This
also works if the PCs in the LAN do not have any static DNS entries, but are
assigned these dynamically by X4000 as DHCP server.
Forwarding entries enable X4000 to decide which DNS is to be used for the
resolution of certain names. If you have configured two WAN partners in X4000 ,
your head office and your Internet Service Provider, it is advisable to have
Internet names resolved by the DNS of your ISP, but names from within the
corporate network by the DNS of the head office. A DNS request for resolution
of an internal company address usually cannot be answered by the DNS of the
ISP and is thus superfluous, causes unnecessary costs and resolution takes
longer than necessary. A forwarding entry, which passes DNS requests for
names such as "*.intranet.de" to the WAN partner "head office", is therefore
advisable.
DNS cache If a DNS request is passed by X4000 to a DNS and this DNS answers with a
DNS record, the resolved name is saved with the associated IP address as a
positive dynamic entry in the DNS cache of X4000 . This means that once a
name has been resolved and is required again, X4000 can answer the request