Routing

hello group,

The 2 NICs on my machine, which is NOT connected to the Internet are
as follows:

eth0
IP: 10.2.255.253
B'cast:10.2.255.255
mask:255.255.255.253

eth1
IP:10.2.240.234
B'cast:10.2.247.255
mask:255.255.248.0

When i try to ping hosts either side of the Linux machine from the
respective machines that lie side by sideof the linux router it does
not respond. It only reaches the opposite side network
interface,dosn't go beyond that to the intended machine. But from the
Linux machine i could ping the hosts individually. I have enabled
ip_forwarding through /etc/sysctl.conf. /proc/sys/net/ipv4/ip_forward
also echos to 1.
For Ex:
Assume there is a machine 10.2.240.235 on the network eth1 is
connected to and i want to ping 10.2.255.254 which is in the network
connecting to eth0. When i try to ping 10.2.240.236 from 10.2.255.254
it stays blank. Well these two machine i refer here are 2 CISCO 2705
routers. My network expert says that there is no issue in the routers.
Infact he showed me the same setup having one of his routers in the
middle. Help me to get over this. Do i have to run some routing
protocol to bet about doing this?.

Thanks for your time.

Hello Thamara.

I Think in first your Netmask from your eth0 is wrong. it is Posible to have
a Netmask like 255.255.255.252 and 255.255.255.254 but 253 isn`t Posible. If
you want do make a Net with only 2 Hosts you have to take the Netmask
255.255.255.252 there is 10.2.255.255 the Broadcast Adress, 10.2.255.252 th
Net Adress and 253 and 254 can you tahe for the Hosts. In my Opinion it will
work if you change this.

Michael


"Thamara" <thamara.wanigatunga@eureka.lk> schrieb im Newsbeitrag
news:6eb2987e.0311050155.3c9bb1e5@posting.google.c om...
> hello group,
>
> The 2 NICs on my machine, which is NOT connected to the Internet are
> as follows:
>
> eth0
> IP: 10.2.255.253
> B'cast:10.2.255.255
> mask:255.255.255.253
>
> eth1
> IP:10.2.240.234
> B'cast:10.2.247.255
> mask:255.255.248.0
>
> When i try to ping hosts either side of the Linux machine from the
> respective machines that lie side by sideof the linux router it does
> not respond. It only reaches the opposite side network
> interface,dosn't go beyond that to the intended machine. But from the
> Linux machine i could ping the hosts individually. I have enabled
> ip_forwarding through /etc/sysctl.conf. /proc/sys/net/ipv4/ip_forward
> also echos to 1.
> For Ex:
> Assume there is a machine 10.2.240.235 on the network eth1 is
> connected to and i want to ping 10.2.255.254 which is in the network
> connecting to eth0. When i try to ping 10.2.240.236 from 10.2.255.254
> it stays blank. Well these two machine i refer here are 2 CISCO 2705
> routers. My network expert says that there is no issue in the routers.
> Infact he showed me the same setup having one of his routers in the
> middle. Help me to get over this. Do i have to run some routing
> protocol to bet about doing this?.
>
> Thanks for your time.

"Thamara" <thamara.wanigatunga@eureka.lk> wrote in message
news:6eb2987e.0311050155.3c9bb1e5@posting.google.c om...
>
> eth0
> IP: 10.2.255.253
> B'cast:10.2.255.255
> mask:255.255.255.253
>

The mask is incorrect: there must be no ones on right side of the first
zero.

The possible values for the last byte can be:

11111100 = 252,
11111000 = 248,
11110000 = 240,
11100000 = 224,
11000000 = 192,
10000000 = 128 or
00000000 = 0.

Please note that in normal use 11111110 = 254 does not give a sensible
subnet: the only addresses available go to the network address and broadcast
address.

(Yes, I know about CIDR!).

HTH

Tauno Voipio
tauno voipio @ iki fi

On Wed, 05 Nov 2003 01:55:08 -0800, Thamara wrote:

> hello group,
>
> The 2 NICs on my machine, which is NOT connected to the Internet are
> as follows:
>
> eth0
> IP: 10.2.255.253
> B'cast:10.2.255.255
> mask:255.255.255.253
>
> eth1
> IP:10.2.240.234
> B'cast:10.2.247.255
> mask:255.255.248.0
>
> When i try to ping hosts either side of the Linux machine from the
> respective machines that lie side by sideof the linux router it does
> not respond. It only reaches the opposite side network
> interface,dosn't go beyond that to the intended machine. But from the
> Linux machine i could ping the hosts individually. I have enabled
> ip_forwarding through /etc/sysctl.conf. /proc/sys/net/ipv4/ip_forward
> also echos to 1.
> For Ex:
> Assume there is a machine 10.2.240.235 on the network eth1 is
> connected to and i want to ping 10.2.255.254 which is in the network
> connecting to eth0. When i try to ping 10.2.240.236 from 10.2.255.254
> it stays blank. Well these two machine i refer here are 2 CISCO 2705
> routers. My network expert says that there is no issue in the routers.
> Infact he showed me the same setup having one of his routers in the
> middle. Help me to get over this. Do i have to run some routing
> protocol to bet about doing this?.
>
> Thanks for your time.

Wow Dude you used 23 bits in that last octet netmask on eth0.
Thats just wrong...well pointless actually.

Here is a cool online subnet calculator:
http://txweb.tactix.com/subnet.html

This is the wrong newsgroup for this question.
Try: comp.dcom.sys.cisco

Go back and redo your subnetting.
Hint: borrow less bits.

Then start from layer 1 when you set up the two routers and any hosts on
each subnetwork.

Then start on layer 2.
Enable routing, keep it simple ie: RIP

http://www.cisco.com/pcgi-bin/Suppor...networking:RIP

Seriously dude, wipe out whatever lame config is on those routers and
start from layer 1 again.

Good Luck

--
GNU/Linux is God
get used to it
declinton@sympatico.ca
Linux User # 276385