Switching between 2 internet connections

[jonathan.gross]

Hello,

I have 2 NICs in my computer, connected to different networks with
different internet connections (one for each network).

Usually, my computer is connected to the internet through NIC 1 and
network 1 (I checked it with tracert).

Sometimes the connection to the internet in network 1 is down for
whatever reason and i switch to the second lan by doing the following:
1. I clean the routing table of windows xp, in CMD: "route -f"
1. disable and enable TCP/IP in NIC 2, which adds a record to the
routing table.

In order to revert back to NIC 1, i repeat the same procedure for NIC
1.

My question is whether there is a cleaner way to do the same, maybe
even make Windows somehow automatically detect that internet is down on
network 1 and switch to network 2 (preferebly without writing scripts
to modify Metrics and interfaces or so).

Thanks.

 

[Chuck]

Hello,

I have 2 NICs in my computer, connected to different networks with
different internet connections (one for each network).

Usually, my computer is connected to the internet through NIC 1 and
network 1 (I checked it with tracert).

Sometimes the connection to the internet in network 1 is down for
whatever reason and i switch to the second lan by doing the following:
1. I clean the routing table of windows xp, in CMD: "route -f"
1. disable and enable TCP/IP in NIC 2, which adds a record to the
routing table.

In order to revert back to NIC 1, i repeat the same procedure for NIC
1.

My question is whether there is a cleaner way to do the same, maybe
even make Windows somehow automatically detect that internet is down on
network 1 and switch to network 2 (preferebly without writing scripts
to modify Metrics and interfaces or so).

Thanks.

Jonathan,

Try using the Automatic Metric feature in Windows XP. If you adjust the metric
so NIC 1 is preferable over NIC 2, and activate both NICs, you should use NIC 1
whenever it is online.
<http://nitecruzr.blogspot.com/2005/05/have-laptop-will-travel.html#Dual>

 

[Steve Winograd [MVP]]

Hello,

I have 2 NICs in my computer, connected to different networks with
different internet connections (one for each network).

Usually, my computer is connected to the internet through NIC 1 and
network 1 (I checked it with tracert).

Sometimes the connection to the internet in network 1 is down for
whatever reason and i switch to the second lan by doing the following:
1. I clean the routing table of windows xp, in CMD: "route -f"
1. disable and enable TCP/IP in NIC 2, which adds a record to the
routing table.

In order to revert back to NIC 1, i repeat the same procedure for NIC
1.

My question is whether there is a cleaner way to do the same, maybe
even make Windows somehow automatically detect that internet is down on
network 1 and switch to network 2 (preferebly without writing scripts
to modify Metrics and interfaces or so).

Thanks.

There's no need to modify the route table or to disable and enable
TCP/IP.

When network 1 goes down, disable the network connection that uses it.
When you want to try network 1 again, enable the network connection
that uses it.

To make sure that the computer uses network 1 when both networks are
enabled, assign a metric value to both network connections, giving a
lower value to the connection for network 1.
--
Best Wishes,
Steve Winograd, MS-MVP (Windows Networking)

Please post any reply as a follow-up message in the news group
for everyone to see. I'm sorry, but I don't answer questions
addressed directly to me in E-mail or news groups.

Microsoft Most Valuable Professional Program
http://mvp.support.microsoft.com

 

[jonathan.gross]

Thank you for the quick responses,

Chuck, your proposed method was what I've already tried. I've given NIC
2 (which is a firewire connection) the lower metric. but when I
disconnected NIC 2, NIC 1 (ethernet) was not being used.
But reversing the order (giving the ethernet connection the lower
metric) seems to work.
I think this weird behaviour is due to the fact that when a firewire
connection is disconnected, its entry in the routing table remains, but
when en ethernet connection id disconnected its entry is removed (by
looking at the "route print" output).

Did anyone encountered this before ? an if so is there a way to fix it ?

 

[Chuck]

Thank you for the quick responses,

Chuck, your proposed method was what I've already tried. I've given NIC
2 (which is a firewire connection) the lower metric. but when I
disconnected NIC 2, NIC 1 (ethernet) was not being used.
But reversing the order (giving the ethernet connection the lower
metric) seems to work.
I think this weird behaviour is due to the fact that when a firewire
connection is disconnected, its entry in the routing table remains, but
when en ethernet connection id disconnected its entry is removed (by
looking at the "route print" output).

Did anyone encountered this before ? an if so is there a way to fix it ?

Jonathan,

I think you've got it right. Firewire might give you 100 (aka S100) to 400 (aka
S400) Mb/sec, which is comparable to Ethernet at 100 (or 1000 if you're setup
for Gigabit) Mb/sec. If you're using Automatic metric, Ethernet would be
preferred. So, by giving the Ethernet connection a lower value, you're getting
what you're looking for.

According to the article:
Greater than 200 Mb 10
Greater than 20 Mb, and less than or equal to 200 Mb 20
Greater than 4 Mb, and less than or equal to 20 Mb 30
Greater than 500 kilobits (Kb), and less than or equal to 4 Mb 40
Less than or equal to 500 Kb 50

I guess it depends upon what Firewire version you have.