multiple gateways

efm · 06-09-2005, 11:37 PM

Hello,

Can i use multiple gateways in Linux just like in Windows? I´m new in Linux,
and I love it because I can use aliases to my IP address. Windows can´t (I think),
but it can use multiple gateways.
My computer IP is 192.168.2.253, and the gateway at the factory is 192.168.2.3,
and sometimes I have to go to the main office, and their gateway is 192.168.1.3,
so I made alias to the real IP with 192.168.1.253. Therefore, with Linux,
I don´t have to change my IP address, but too bad I have to change the gateway
in my computer.

Any suggestion?

Thank you

michaelsanford · 06-10-2005, 01:08 AM

Code:

ifconfig eth0:0 192.168.1.253
ifconfig eth0:1 192.168.2.253
route add default gw 192.168.2.3 via dev eth0
route add default gw 192.168.1.3 via dev eth0

The first two lines set up ip alias so that your eth0 interface can see both 192.168.1/2 networks, and the second two add a new default gateway for each network segment. It may sound counter-intuitive but you can in fact have more than one default gateway; this becomes clear once you realise that they're in different subnets. See mine:

Code:

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.0.0     *               255.255.255.0   U     0      0        0 eth0
192.168.1.0     *               255.255.255.0   U     0      0        0 eth0
10.0.0.0        *               255.0.0.0       U     0      0        0 wlan0
loopback        *               255.0.0.0       U     0      0        0 lo
default         192.168.0.1     0.0.0.0         UG    0      0        0 eth0
default         192.168.1.1     0.0.0.0         UG    1      0        0 eth0

I hope I haven't made any stupid mistakes...it's been a rough evening.

gd2shoe · 06-10-2005, 02:21 AM

Just here to learn. Are you sure about "via"; I couldn't find it in the man page?

Quote:

Originally posted by michaelsanford

Code:

ifconfig eth0:0 192.168.1.253
ifconfig eth0:1 192.168.2.253
route add default gw 192.168.2.3 via dev eth0
route add default gw 192.168.1.3 via dev eth0

....

I hope I haven't made any stupid mistakes...it's been a rough evening.

I think you might have. Then again, I'm not an authority. If there is some meaning I would be thrilled to learn it.

efm · 06-10-2005, 02:33 AM

Hello, thanks for replies
but the ¨route add...¨ lines are not working,
but i think i get the idea and i want to try it using yast
thank you

michaelsanford · 06-10-2005, 08:50 AM

Woops! Yeah there's no via, it's just route dev eth0.