Questions[eth0](server)

My goal is to set two ethernet interfaces on two different ports and with two differents static IP on the same network. The matter is that one port will become reachable by the two IPs, the other won't. I proceed with the /etc/network/interfaces file and /etc/init.d/networking restart call. I also tried with ifupdown calls. Here is how I proceed:

I've just installed my Debian 3.16 OS without any network configuration.My device has two Ethernet ports.

ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
    link/ether 00:30:18:cd:49:77 brd ff:ff:ff:ff:ff:ff
3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000
    link/ether 00:30:18:cd:49:76 brd ff:ff:ff:ff:ff:ff
4: wlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether bc:30:7e:c0:e6:ba brd ff:ff:ff:ff:ff:ff

ifconfig
lo        Link encap:Boucle locale  
          inet adr:127.0.0.1  Masque:255.0.0.0
          adr inet6: ::1/128 Scope:Hôte
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:31 errors:0 dropped:0 overruns:0 frame:0
          TX packets:31 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 lg file transmission:0 
          RX bytes:3172 (3.0 KiB)  TX bytes:3172 (3.0 KiB)

cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

Everything seems fine. I want to add a new ethernet interface to connect on my network, so I modify the /etc/network/interfaces file this way:

cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet static
address 192.168.1.160
netmask 255.255.255.0
gateway 192.168.1.1

My device is now reachable on ethernet port let's say A with the IP 192.168.1.160, ifconfig is fine too. Then I add the new interface and modify /etc/network/interfaces this way:

cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address 192.168.1.160
netmask 255.255.255.0
gateway 192.168.1.1

auto eth1
iface eth1 inet static
address 192.168.1.161
netmask 255.255.255.0
gateway 192.168.1.1


ifconfig
eth0      Link encap:Ethernet  HWaddr 00:30:18:cd:49:77  
          inet adr:192.168.1.160  Bcast:192.168.1.255  Masque:255.255.255.0
          adr inet6: fe80::230:18ff:fecd:4977/64 Scope:Lien
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:6550 errors:0 dropped:8 overruns:0 frame:0
          TX packets:819 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 lg file transmission:1000 
          RX bytes:584489 (570.7 KiB)  TX bytes:106896 (104.3 KiB)
          Interruption:18 Mémoire:d0700000-d0720000 

eth1      Link encap:Ethernet  HWaddr 00:30:18:cd:49:76  
          inet adr:192.168.1.161  Bcast:192.168.1.255  Masque:255.255.255.0
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:222 errors:0 dropped:0 overruns:0 frame:0
          TX packets:12 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 lg file transmission:1000 
          RX bytes:20241 (19.7 KiB)  TX bytes:1500 (1.4 KiB)
          Interruption:19 Mémoire:d0600000-d0620000 

lo        Link encap:Boucle locale  
          inet adr:127.0.0.1  Masque:255.0.0.0
          adr inet6: ::1/128 Scope:Hôte
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:31 errors:0 dropped:0 overruns:0 frame:0
          TX packets:31 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 lg file transmission:0 
          RX bytes:3172 (3.0 KiB)  TX bytes:3172 (3.0 KiB)

I expect to reach my device on port A with .160 and on port B with .161. But I actually reach my device on port A with both .160 and .161, and none on port B.

EDIT: If I plug the Ethernet cable on the physical port A, I want to be able to join (ping or ssh connexion) my device with IP 192.168.1.160. If I plug the Ethernet cable on the physical port B, I want to be able to join (ping or ssh connexion) my device with IP 192.168.1.161. (network is 192.168.1.0/24)

My questions are:

• What I am doing wrong? Are those file and calls aim to work together or are they non-compatible in their network management?
• What are the tools commonly used to configure a network interface on Debian 3.16 if not those one?
• Is there a link I've missed between network interfaces and the hardware?

Of course:

1. I've spent lot of time looking for some answers and build my method with thoses answers, plus the network configuration for Debian documentation.
2. I've tried to restart network interfaces with both /etc/init.d/networking restart and ifup/ifdown eth0
3. Finally I've re-installed my Debian for that, so I also tried to reboot.

Whenever I reboot a CentOS Hyper-V VM, eth0 does not start automatically. All I need to do is perform ifup eth0 and all is fixed, but that isn't feasible from ssh! I am starting in runlevel 3.

[root@localhost ~]# cat /etc/*release*
CentOS release 6.2 (Final)

After I perform ifup eth0 on the console:

[root@localhost ~]# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:15:5D:2B:2B:07
      inet addr:10.10.0.3  Bcast:10.10.0.255  Mask:255.255.255.0
      inet6 addr: fe80::215:5dff:fe2b:2b07/64 Scope:Link
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:34 errors:0 dropped:0 overruns:0 frame:0
      TX packets:49 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000
      RX bytes:4656 (4.5 KiB)  TX bytes:6399 (6.2 KiB)
      Interrupt:9 Base address:0xa000

[root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
BOOTPROTO=none
IPADDR=10.10.0.3
NETMASK=255.255.255.0
GATEWAY=10.10.0.1
USERCTL=no
ONBOOT=yes

[root@localhost ~]# chkconfig --list | grep network
network         0:off   1:off   2:on    3:on    4:on    5:on    6:off

After trying to turn off Network Manager

[root@localhost ~]# chkconfig NetworkManager off
error reading information on service NetworkManager: No such file or directory
[root@localhost ~]# service NetworkManager status
NetworkManager: unrecognized service

[root@localhost ~]# grep eth0 /var/log/messages
Jul  7 02:12:44 localhost kernel: eth0: Digital DS21140 Tulip rev 32 at MMIO 0xfebff000, 00:15:5d:2b:2b:07, IRQ 9.
Jul  7 02:13:15 localhost kernel: eth0: Using EEPROM-set media 100baseTx-FDX.

[root@localhost ~]# dmesg | grep eth0
eth0: Digital DS21140 Tulip rev 32 at MMIO 0xfebff000, 00:15:5d:2b:2b:07, IRQ 9.
eth0: Using EEPROM-set media 100baseTx-FDX.
eth0: no IPv6 routers present

[root@localhost ~]# ifup eth0
/etc/sysconfig/network-scripts/ifup-ipv6: line 56: /etc/sysconfig/network: No such file or directory
/etc/sysconfig/network-scripts/ifup-aliases: line 125: /etc/sysconfig/network: No such file or directory

I have seen many posts explaining bridging eth and wlan interfaces. I would like to know if it is possible to bridge ppp0 interface (a USB modem) and eth0. I have a working internet connection through ppp0 interface. I want a DHCP server set up listening at the eth0 interface and assigning addresses to share internet connection received from ppp0.

On CentOS I no longer have a ifcfg-eth0 configuration file (I deleted it). When I run system-configure-network it shows no interfaces that I can edit. How can I recreate the ifcfg-eth0 configuration file? (Like the CentOS installer does)

I can manually do a: ifconfig eth0 192.168.0.199 and then a ping 192.168.0.1. But that's not the proper way. How can I do it using the CentOS network scripts?

I prefer not to do this by hand as there are many hardlinks and confusing stuff. I am new to CentOS.

I have a small server with a single NIC that I am trying to get a bridge functioning on so that I can run KVM. On this NIC I have a couple IPs statically assigned to it:

eth0 = 192.168.1.1
eth0:1 = 192.168.1.2
eth0:2 = 192.168.1.3
eth0:3 -> Assign the bridge to this

I am attempting to set up a bridge using the following instructions:

sudo brctl addbr br0
sudo brctl addif br0 eth0:3
sudo ifconfig br0 192.168.1.120 netmask 255.255.255.0 up
sudo route add -net 192.168.1.0 netmask 255.255.255.0 br0
sudo route add default gw 192.168.1.1 br0
sudo tunctl -b -u root -t tap0 > /dev/null
sudo ifconfig tap0 up
sudo brctl addif br0 tap0

However, when I do the second command:

sudo brctl addif br0 eth0:3

It puts the ENTIRE eth0 device into promiscuous mode. This knocks the server offline and inaccessible by anything other than locally.

Is there a way to bridge JUST eth0:3 to br0 and not put the entire device into promiscuous mode?