Reference Manual
HOW TO fix Windows IP Autoconfiguration Problems:
Windows 98 and 2000 support a mechanism called IP Autoconfiguration,
which aims to relieve the user of the task of configuring the TCP/IP protocol
when a Network Adapter is added to the system. The mechanism works as follows:
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After the new Network Adapter has been added, Windows automatically binds
the TCP/IP "Protocol" to that adapter. If no further steps are taken by
the user, that Protocol is set to "Obtain an IP address automatically".
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When the machine next boots, Windows runs the DHCP protocol on that adapter
and tries to contact a DHCP Server.
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If a DHCP Server cannot be reached (the usual case for private LANs), Windows
assigns a special IP address of 169.254.x.y to that adapter.
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Thereafter, Windows retries the DHCP configuration at 3-minute intervals,
and reconfigures the adapter if a DHCP Server can be contacted.
The problems with this mechanism are:
-
Most private LANs do not have a DHCP Server running, and so the initial
DHCP configuration attempt will always fail. This futile configuration
attempt will waste about 30 seconds each time you boot the machine.
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Thereafter, at 3-minute intervals, many networking applications will block
for about 30 seconds while Windows is in the process of reconfiguration.
This manifests itself as inactivity in those networking applications, and
some applications may even appear to "hang". To illustrate this effect,
try running winipcfg.exe on Windows 98. Whenever reconfiguration
is taking place, the winipcfg dialog box is not redrawn and the
application appears to have crashed. Waiting up to 30 seconds will fix
things, but the novice user may not know this.
The solution is simple: always assign a fixed private IP address to
network adapters that cannot reach a DHCP Server. You should only
use IP Autoconfiguration on adapters which usually can reach a DHCP
Server.
Some one-way Cable Modem users will have been told by their ISP to enable
IP Autoconfiguration on the Ethernet Adapter which connects to the Cable
Modem. Such ISPs usually recommend this for simplicity, being unaware of
the problems it causes. It is best to configure such adapters as follows:
IP Address: 10.1.1.1
Mask: 255.0.0.0
Gateway: none
When NAT32 is to be installed on a system with a private LAN Adapter, you
should always use a private Class B IP address on that adapter.
In fact, the Adapter should be configured as follows:
IP Address: 172.16.1.1
Mask: 255.255.255.0
Gateway: none
You should also always enable DNS, giving the host a name of your
choice on the Domain of your ISP. The DNS address specified should be the
address of a fast, reliable DNS server in your vicinity.
SEE ALSO
clients dhcpd