25.4 Internet links dialed on demand
383
will be dialed upon a client’s DNS query. If a local DNS server is used, the line will be
dialed upon a query sent by this server to the Internet (the default gateway of the host
where the DNS server is running must be set to the IP address of the
WinRoute
host).
3.
It can be easily understood through the last point that if the DNS server is to be running at
the
WinRoute
host, it must be represented by
DNS Forwarder
because it can dial the line
if necessary.
If there is a domain based on
Active Directory
in the LAN (domain server with
Windows
Server 2000/2003/2008
), it is necessary to use
Microsoft
DNS server, because communica-
tion with
Active Directory
uses special types of DNS request.
Microsoft
DNS server does not
support automatic dialing. Moreover, it cannot be used at the same host as
DNS Forwarder
as it would cause collision of ports.
As understood from the facts above, if the Internet connection is to be available via dial-
up,
WinRoute cannot
be used at the same host where
Windows Server
with
Active Directory
and
Microsoft
DNS are running.
4.
If
DNS Forwarder
is used,
WinRoute
can dial as a response to a client’s request if the
following conditions are met:
•
Destination server must be defined by DNS name so that the application can create
a DNS query.
•
In the operating system, set the primary DNS server to the IP address of the fire-
wall). In
Windows
, go to TCP/IP properties in interfaces connected to the LAN and
set the IP address of this interface as the primary DNS server.
5.
The
Proxy server
in
WinRoute
(see chapter
) also provides direct dial-up connections.
A special page providing information on the connection process is opened (the page is
refreshed in short periods). Upon a successful connection, the browser is redirected to
the specified Website.
Unintentionally dialed link — application of on-demand dial rules
Demand dial functions may cause unintentional dialing. It’s usually caused by DNS queries
that are handled by the
DNS Forwarder
The following causes apply:
•
User host generates a DNS query in the absence of the user. This traffic attempt may be
an active object at a local HTML page or automatic update of an installed application.
•
DNS Forwarder
performs dialing in response to requests of names of local hosts. De-
fine DNS for the local domain properly (use the
hosts
system file of the
WinRoute
host
— for details, see chapter
Note:
Undesirable traffic causing unintentional dialing of a link can be blocked by
WinRoute
traffic rules (see chapter
). However, the best remedy for any pain is always removal of its
cause (e.g. perform antivirus check on the corresponding workstation, etc.).
Summary of Contents for Firewall6
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