My question is "How do I bind each of my server's NIC's to a separate IP?"
My Ubuntu 12.04 server has two NIC's - both are attached to my home lan.
The NIC's have device names that were set in /etc/udev/rules.d/70-persistent-net.rules. I have called the lan0 and lan1. (see below for my 70-persistent-net.rules).
Each NIC acquires correctly its IP settings via DHCP from my router. The assignment of IP is done based on the MAC of the dhcp request. lan0 is assigned ip 172.23.80.1 whilst lan1 is assigned 172.23.80.2. (see below for ifconfig output and my /etc/network/interfaces).
My problem is that when I connect via ssh from a separate computer I always receive the connection from the same server MAC irrespective of the ip that I used in the ssh call.
Let me describe the following experiment that shows my problem. I use three terminals (term1, term2 and term3) on my Ubuntu desktop computer
term1:
arp -n
Address HWtype HWaddress Flags Mask Iface
172.16.0.1 ether 00:50:7f:9d:2d:30 C wlan0
172.23.80.1 (incomplete) wlan0
term2:
ssh me@172.23.80.1
me@172.23.80.1's password:
Welcome to Ubuntu 12.04.1 LTS (GNU/Linux 3.2.0-29-generic-pae i686)
* Documentation: https://help.ubuntu.com/
Last login: Thu Aug 16 12:37:48 2012 from 172.23.128.11
me@FERMI:~$
term1:
arp -n
Address HWtype HWaddress Flags Mask Iface
172.16.0.1 ether 00:50:7f:9d:2d:30 C wlan0
172.23.80.1 ether 00:0d:61:22:3d:d6 C wlan0
term3:
ssh me@172.23.80.2
me@172.23.80.2's password:
Welcome to Ubuntu 12.04.1 LTS (GNU/Linux 3.2.0-29-generic-pae i686)
* Documentation: https://help.ubuntu.com/
Last login: Thu Aug 16 13:37:12 2012 from 172.23.128.11
me@FERMI:~$
term1:
arp -n
Address HWtype HWaddress Flags Mask Iface
172.23.80.2 ether 00:0d:61:22:3d:d6 C wlan0
172.16.0.1 ether 00:50:7f:9d:2d:30 C wlan0
172.23.80.1 ether 00:0d:61:22:3d:d6 C wlan0
As you can see from this last arp both ssh connections are being serviced by a single NIC on the server even though the two ip's have been assigned to different NICs. This is my problem.
Here is my Server configuration:
me@FERMI:~$ ifconfig
lan0 Link encap:Ethernet HWaddr 00:0d:61:22:3d:d6
inet addr:172.23.80.1 Bcast:172.31.255.255 Mask:255.240.0.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1452 errors:0 dropped:0 overruns:0 frame:0
TX packets:496 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:113691 (113.6 KB) TX bytes:72934 (72.9 KB)
lan1 Link encap:Ethernet HWaddr 00:19:5b:68:93:57
inet addr:172.23.80.2 Bcast:172.31.255.255 Mask:255.240.0.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1103 errors:0 dropped:0 overruns:0 frame:0
TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:85747 (85.7 KB) TX bytes:684 (684.0 B)
Interrupt:22 Base address:0x9000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:14 errors:0 dropped:0 overruns:0 frame:0
TX packets:14 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:700 (700.0 B) TX bytes:700 (700.0 B)
me@FERMI:~$ 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).
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
auto lan0
iface lan0 inet dhcp
auto lan1
iface lan1 inet dhcp
me@FERMI:~$ cat /etc/udev/rules.d/70-persistent-net.rules
# This file was automatically generated by the /lib/udev/write_net_rules
# program, run by the persistent-net-generator.rules rules file.
#
# You can modify it, as long as you keep each rule on a single
# line, and change only the value of the NAME= key.
# PCI device 0x1186:/sys/devices/pci0000:00/0000:00:1e.0/0000:03:02.0 (sundance)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:19:5b:68:93:57", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="lan1"
# PCI device 0x8086:/sys/devices/pci0000:00/0000:00:03.0/0000:02:01.0 (e1000)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0d:61:22:3d:d6", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="lan0"
me@FERMI:~$ route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default OHM.UNIVERSE 0.0.0.0 UG 100 0 0 lan0
172.16.0.0 * 255.240.0.0 U 0 0 0 lan0
172.16.0.0 * 255.240.0.0 U 0 0 0 lan1
me@FERMI:~$ cat /proc/sys/net/ipv4/ip_forward
0
me@FERMI:~$ arp -n
Address HWtype HWaddress Flags Mask Iface
172.23.128.11 ether 00:18:de:02:f0:5c C lan0
172.16.0.1 ether 00:50:7f:9d:2d:30 C lan0
me@FERMI:~$ sudo ufw status
Status: inactive
