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[ubuntu] Use Linux box with one NIC as Router

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http://ubuntuforums.org – Hello community, Is it possible to use a Linux box with just one Ethernet NIC as a router, creating virtual interfaces, thus having two IP addresses on one physical network card? eth0 192.168.2.1 (local router IP address and netmask) eth0:0 (WAN IP Address and Netmask) Then use IPtables and routing to direct traffic from eth0:0 to eth0 and back (or maybe use bridging if that's possible for virtual interfaces?). Please leave your suggestions and comments. Thank you, -Beboy ()

xskl's picture
Submitted by xskl on 10/02/2012

Stories similar to [ubuntu] Use Linux box with one NIC as Router

New to linux networking, had a question about routing to virtual ip addresses from a different subnet.

I have three servers (they can all ping each other):

A 10.10.51.182 (connected to router Y) B 10.10.51.183 (connected to router Y) C 10.10.60.10 (connected to router Z)

On server A, I created 1000 virtual interfaces:

# ifconfig eth0:0 192.168.1.1 netmask 255.255.0.0 # ifconfig eth

Hi All,

I have 2 NICs in my U9.04 Server box (eth0, eth1). After I added 2 virtual interfaces for each physical interface (eth0:1,eth0:2,eth1:1,eth1:2), the MAC addresses of all the interfaces have changed to that of eth0. Because eth1 was configured to be on my local network, I can't access the box remotely anymore.

I have debian hosts which are connected through trunk port on 5 different vlans. But this host respond to arp "who-has" requests of all of their differents ip.

Hi I'm trying to set up Clonezilla on a fresh Ubuntu install, following this tutorial: http://geekyprojects.com/cloning/set...ver-on-ubuntu/

It mostly works out ok, but i have some problems setting up the virtual network card.

my question is as simple as the title, i have a debian 6 , 2 NICs, 3 different subnets in a single interface, just like this:

auto eth0 iface eth0 inet static address 192.168.106.254 netmask 255.255.255.0

auto eth0:0 iface eth0:0 inet static address 172.19.221.81 netmask 255.255.255.248

auto eth0:1 iface eth0:1 inet static address 192.168.254.1 netmask 255.255.255.248

Because of a bug in Ubuntu 11.10 it is not possible to bridge NIC's as of this writing, so I assume that I have to bridge and setup ucarp in /etc/rc.local.

I can bridge eth0 just fine with

ifconfig eth0:1 10.10.69.19 netmask 255.255.252.0 broadcast 10.10.71.255

so I have to convert the rest of the ucarp config from /etc/network/interfaces which is

# used for ssh auto eth0 iface eth0 inet stati

The IP does no longer respond to a remote ping

With restart I mean:

lxc-stop -n vm3 lxc-start -n vm3 -f /etc/lxc/vm3.conf -d

--

/etc/network/interfaces

auto lo iface lo inet loopback up route add -net 127.0.0.0 netmask 255.0.0.0 dev lo down route add -net 127.0.0.0 netmask 255.0.0.0 dev lo

# device: eth0 auto eth0 iface eth0 inet manual

auto br0 iface br0 inet static address 192.22

I used command

iptables -t nat -I POSTROUTING -o $INTERFACE -p tcp -j SNAT --to-source $IP

to make my server packets visible as $IP. But the problem is, that it didn't work inside local area, so when I'm sending something to address 10.X.X.X, then I'm not visible as $IP, but as older IP.

EDIT: There are 3 interfaces:

auto eth0 iface eth0 inet static address 46.X.X.152 netmask 255.255

I've setup Ubuntu server along with ufw as a firewall.

To start, I have two networks:

Public: 66.xxx.xxx.70 - 66.xxx.xxx.78

Private: 192.168.3.1 - 192.168.3.255

My network config:

auto eth0 iface eth0 inet static address 66.xxx.xxx.70 netmask 255.255.255.0 network 66.xxx.xxx.0 broadcast 66.xxx.xxx.255 gateway 66.xxx.xxx.1

auto eth0:0 iface eth0:0 inet