configuring two NIC's on single machine

b0nd · 10-05-2005, 09:15 PM

Hello all,
i've two systems, one desktop and other one is laptop.
desktop is connected to internet using ethernet ADSL modem ( so engaging my lan card )

Now i would like to bring my laptop too to internet, using desktop as gateway.
so i plugged one more NIC in the desktop machine.

Now is there any trap in configuring them ???
i mean..............if they are same, then need to compile kernel....
or............the subnet mask should not be the same etc etc..

i'm googling parallely.........but in order to have proper guidance i'm firing this query

regards

samac · 10-06-2005, 04:08 AM

Hi

I have the same sort of setup, except the second card goes to a hub. All you need to do is modify your /etc/rc.d/rc.inet1.conf with some details for your card. I use a static IP address on eth1 and dhcp on eth0.

Then restart /etc/rc.d/rc.inet1 and maybe rc.inet2 if you have a firewall script and it has been modified to allow you to access the internet from your laptop.

Calling ifconfig -a should then with any luck show your card.

Samac

Alien Bob · 10-06-2005, 04:47 AM

All the information you need is on your local hard disk....
Read /usr/doc/Linux-HOWTOs/DSL-HOWTO and especially paragraph 8.5. Setting up Linux as a Router
If that does not answer all your questions, feel free to add to this topic.

Cheers, Eric

b0nd · 10-06-2005, 09:45 AM

Hello,
i did some hit and trial methods.
since the IP of my modem is 192.168.1.1, so to the NIC to which it is connected, i've assigned the static IP 192.168.1.2 with netmask value 255.255.255.0.

And to other NIC i.e eth1 i assigned IP ( /etc/rc.d/rc.inet1.conf ) 120.168.0.1 and to laptop 120.168.0.2 with netmask value 255.255.0.0 to both.

Now everything is working fine.

But now i'm googling and doing further experiments to find out whether it was necessary to assign different net mask values and different class address to the two NIC's or not and hence what other combinations could be made.

Thanks to "samac" and "Alien Bob".

regards

Code:

root@bond:~# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:E0:4C:77:13:4F
          inet addr:192.168.1.3  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1074 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1175 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:536547 (523.9 Kb)  TX bytes:176043 (171.9 Kb)
          Interrupt:12 Base address:0xab00

eth1      Link encap:Ethernet  HWaddr 00:A1:B0:10:19:2E
          inet addr:120.168.0.1  Bcast:120.168.255.255  Mask:255.255.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
          Interrupt:10 Base address:0xcc00

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:74 errors:0 dropped:0 overruns:0 frame:0
          TX packets:74 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:5012 (4.8 Kb)  TX bytes:5012 (4.8 Kb)

Alien Bob · 10-06-2005, 01:51 PM

My advice;

Do not use those addresses 120.168.0.1 and 120.168.0.2 because they are existing IP addresses out there on the Internet. For home and other internal use, a whole lot of IP addresses are available that you will never find on the Internet.

The range 192.168.0.0/255.255.0.0 is available for private use, for instance.
So are the ranges 10.0.0.0/255.0.0.0 and 172.16.0.0/255.240.0.0.
So, it would look better if you change 120.168.0.1/255.255.0.0 and 120.168.0.2/255.255.0.0 to 192.168.0.1/255.255.255.0 and 192.168.0.2/255.255.255.0.

Be sure to use the 255.255.255.0 netmask so that these new IP addresses are outside the IP address range of the other addresses 192.168.1.1/255.255.255.0 and 192.168.1.2/255.255.255.0.

Eric