Default Gateway Addresses Persist in Route Table

Question

Why are the default gateway addresses associated with network interface
cards recorded as persistent routes instead of just becoming an active
route when the network interface is enabled?

This persistence is giving me operational frustrations when trying
to diagnose network configuration issues.

The new TCP/IP stack (deployed in Vista, Win-7, 2008) is causing problems
wherein the default gateway addresses for all network interface cards
are made persistent in the ROUTE table.

Before the network stack re-design (as in: XP, 2000, 2003) the
default gateway addresses were only bound to the network interface
or a virtual interface (i.e. team). These default addresses did not
persist in the ROUTE table.  These network default routes only became
active when the network card was enabled.

I was trying to debug an issue when creating an isolated WORKGROUP
network, and trying to resolve the "unidentified network" problem
which requires that a default gateway address be defined.

A nasty problem occurred when I used the static IP address of the
primary network interface card as the default gateway.  Looking at
the (TCP/IPv4) configuration, the default gateway is empty, but the
ROUTE table shows a persistent route of 0.0.0.0 pointing to the
primary network interface card.  Later, after assigning a reachable
IP address to the primary network interface card, the system shows
both a "Network" location and an "unidentified network" location
bound to the same primary network interface card.

The phantom "unidentified network" location cannot be removed
without invoking  ROUTE  DELETE  0.0.0.0  which removes all default
gateway addresses from all network interfaces along with the persistent
default 0.0.0.0 routes from the ROUTE table.

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Good systems are supportable

Answer 1

Hi,

This forum is for questions related to the Server Core installation option of Windows Server 2008. You should try the Networking forum on TechNet at: http://social.technet.microsoft.com/Forums/en-US/windowsserver2008r2networking/threads

Andrew