Connecting to the internal network

Hi,

I want to connect 2 RedHat Linux 4 servers to my internal network that
I believe assigns IP addresses by DHCP. The 2 servers actually reside
in an IBM bladecenter.

The connection of the servers is from the Cisco switch module of the
bladecenter to an external switch, which is connected to the internal
network point. However, I can't access the network. My workstation
that is connected to the same internal network has an IP address of
192.168.200.X. I'm wondering if the servers can connect to the network
with a static IP address of 192.168.168.X.

Are there any good step-by-step tutorials that can tell me how to
connect the servers to the network?

Thank you.

(E-Mail Removed) a écrit :
> Hi,
>
> I want to connect 2 RedHat Linux 4 servers to my internal network that
> I believe assigns IP addresses by DHCP. The 2 servers actually reside
> in an IBM bladecenter.
>
> The connection of the servers is from the Cisco switch module of the
> bladecenter to an external switch, which is connected to the internal
> network point. However, I can't access the network. My workstation
> that is connected to the same internal network has an IP address of
> 192.168.200.X. I'm wondering if the servers can connect to the network
> with a static IP address of 192.168.168.X.


So you have two IP subnets 192.168.168.0/24 and 192.168.200.0/24 on the
same network and you want them to communicate with each other. Your
options are :

- renumber one subnet so you have only one subnet ;
- change the netmask to 255.255.0.0 (/16) on all machines to merge the
subnets ;
- add direct routes to the other subnet on each machine, i.e. each
machine in 192.168.168.0/24 must have a direct route to 192.168.200.0/24
and vice versa. If this is not possible for machines using DHCP, then
add the route on the routers defined as default gateways for each subnet.

Pascal Hambourg a écrit :
>
> - add direct routes to the other subnet on each machine, i.e. each
> machine in 192.168.168.0/24 must have a direct route to 192.168.200.0/24
> and vice versa. If this is not possible for machines using DHCP

A bit of explaination about this restriction. DHCP provides options to
configure static routes on the clients, BUT

- Both the server and client must support it.

- The old "Static Route" option (option 33) originally defined in RFC
1533 is classfull, i.e. the netmask is implicilty derived from the
destination address, although his is not a problem for 192.168.X.0/24
subnets as 192.168.X.0 were originally class C blocks. Besides, there is
no explicit provision to configure a direct route to a local subnet.

- The new "Classless Static Route" Option (option 121) defined in RFC
3442 addresses both issues of the "Static Route" option. However this
RFC is rather "recent" (2002) so older DHCP server or client
implementations may not support it. Besides, not all IP implementations
may support direct routes to local subnets other than the one defined by
the assigned IP address and mask.

My problem now is that I've tried changing the IP address of the
RedHat servers to 192.168.200.X, but it cannot ping other machines in
the network. I keep getting the "Destination Host Unreachable" error.
I've never tried to configure a Linux machine to connect to an
internal network before, and I'm wondering if there's some
configuration steps that I need to do first.

Thank you.

On Wed, 14 Jan 2009 22:08:15 -0800, (E-Mail Removed) wrote:

> My problem now is that I've tried changing the IP address of the
> RedHat servers to 192.168.200.X, but it cannot ping other machines in
> the network. I keep getting the "Destination Host Unreachable" error.
> I've never tried to configure a Linux machine to connect to an
> internal network before, and I'm wondering if there's some
> configuration steps that I need to do first.

man lspci

lists your hardware, assuming your NIC is modern.

man lsmod

check that the module for your nic is loaded

man ifconfig

probably

ifconfig etho <- should tell you if the NIC is set up properly.

Looks something like

some-host:somedirectory# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:60:67:72:93:A4
inet addr:192.168.X.Y Bcast:192.168.X.255
Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500
Metric:1 RX packets:5361288 errors:0 dropped:0 overruns:0
frame:0 TX packets:31895883 errors:0 dropped:0 overruns:7
carrier:0 collisions:0 txqueuelen:1000
RX bytes:742199991 (707.8 MiB) TX bytes:3212574150 (2.9 GiB)
Interrupt:9 Base address:0x1400



Yes, the X.y is fudging the actual address
>
> Thank you.

On Jan 16, 7:43 am, terryc <newssevenspam-s...@woa.com.au> wrote:
> ifconfig etho <- should tell you if the NIC is set up properly.
>
> Looks something like
>
> some-host:somedirectory# ifconfig eth0
> eth0 Link encap:Ethernet HWaddr 00:60:67:72:93:A4
> inet addr:192.168.X.Y Bcast:192.168.X.255
> Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500
> Metric:1 RX packets:5361288 errors:0 dropped:0 overruns:0
> frame:0 TX packets:31895883 errors:0 dropped:0 overruns:7
> carrier:0 collisions:0 txqueuelen:1000
> RX bytes:742199991 (707.8 MiB) TX bytes:3212574150 (2.9 GiB)
> Interrupt:9 Base address:0x1400
>
> Yes, the X.y is fudging the actual address

I do see that on my servers.

I don't know if anyone here has experience with the IBM BladeCenter.
I'm using the HS21 XM model, with the Cisco Intelligent Gigabit
Ethernet Switch Module. I have 2 ESMs and I'm using Module #1, with
the default IP address 192.168.70.127. I've enabled all external ports
from the Management Module interface. I can ping the switch module
(ESM) from my PC which is directly connected to the Management Module,
but I cannot ping the ESM from the blade server itself (which is
assigned IP address 192.168.70.3). I'm wondering how that could be.

I've tried using DHCP, but it always failed at the "determining eth0
information..." part. I've tried assigning the 192.168.200.X IP
address to the blade servers, but it can't ping other machines on the
200 subnet. So right now, I don't know if it's the hardware (switch)
problem, or a configuration problem.

terryc <newssevenspam-(E-Mail Removed)> writes:

>On Wed, 14 Jan 2009 22:08:15 -0800, (E-Mail Removed) wrote:

>> My problem now is that I've tried changing the IP address of the
>> RedHat servers to 192.168.200.X, but it cannot ping other machines in

What does
route -n
say
It tells you what the routing is.
What are teh IP addresses of your other machines.
Why did you change the IP address to 192.168.299.x

>> the network. I keep getting the "Destination Host Unreachable" error.
>> I've never tried to configure a Linux machine to connect to an
>> internal network before, and I'm wondering if there's some
>> configuration steps that I need to do first.

>man lspci

>lists your hardware, assuming your NIC is modern.

>man lsmod

>check that the module for your nic is loaded

>man ifconfig

>probably

>ifconfig etho <- should tell you if the NIC is set up properly.

>Looks something like

>some-host:somedirectory# ifconfig eth0
>eth0 Link encap:Ethernet HWaddr 00:60:67:72:93:A4
> inet addr:192.168.X.Y Bcast:192.168.X.255
> Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500
> Metric:1 RX packets:5361288 errors:0 dropped:0 overruns:0
> frame:0 TX packets:31895883 errors:0 dropped:0 overruns:7
> carrier:0 collisions:0 txqueuelen:1000
> RX bytes:742199991 (707.8 MiB) TX bytes:3212574150 (2.9 GiB)
> Interrupt:9 Base address:0x1400

That's also a good thing to look at.



>Yes, the X.y is fudging the actual address
>>
>> Thank you.

"(E-Mail Removed)" <(E-Mail Removed)> writes:

>On Jan 16, 7:43 am, terryc <newssevenspam-s...@woa.com.au> wrote:
>> ifconfig etho <- should tell you if the NIC is set up properly.
>>
>> Looks something like
>>
>> some-host:somedirectory# ifconfig eth0
>> eth0 Link encap:Ethernet HWaddr 00:60:67:72:93:A4
>> inet addr:192.168.X.Y Bcast:192.168.X.255
>> Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500
>> Metric:1 RX packets:5361288 errors:0 dropped:0 overruns:0
>> frame:0 TX packets:31895883 errors:0 dropped:0 overruns:7
>> carrier:0 collisions:0 txqueuelen:1000
>> RX bytes:742199991 (707.8 MiB) TX bytes:3212574150 (2.9 GiB)
>> Interrupt:9 Base address:0x1400
>>
>> Yes, the X.y is fudging the actual address

>I do see that on my servers.

You do see WHAT? Details are important.


>I don't know if anyone here has experience with the IBM BladeCenter.
>I'm using the HS21 XM model, with the Cisco Intelligent Gigabit

This has nothing to do with that.

>Ethernet Switch Module. I have 2 ESMs and I'm using Module #1, with
>the default IP address 192.168.70.127. I've enabled all external ports
>from the Management Module interface. I can ping the switch module
>(ESM) from my PC which is directly connected to the Management Module,
>but I cannot ping the ESM from the blade server itself (which is
>assigned IP address 192.168.70.3). I'm wondering how that could be.

>I've tried using DHCP, but it always failed at the "determining eth0
>information..." part. I've tried assigning the 192.168.200.X IP
>address to the blade servers, but it can't ping other machines on the
>200 subnet. So right now, I don't know if it's the hardware (switch)
>problem, or a configuration problem.

Neither do we. Not enough information.

Publish the output to
ifconfig eth0
route -n

I have 3 blade servers:
#1: 192.168.168.201
#2: 192.168.168.202
#3: 192.168.168.203

Technically, I should still be able to access the network from the 168
subnet because it should be able to route to the 200 subnet, if it
were working right.

output of ifconfig eth0 of #1:
eth0 Link encap:Ethernet HWaddr 00:21:5E:22:03:78
inet addr:192.168.168.201 Bcast:192.168.168.255 Mask:
255.255.255.0
inet6 addr: fe80::221:5eff:fe22:3a2/64 Scope: Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:124 errors:0 dropped:0 overruns:0 frame:0
TX packets:51 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:8404 (8.2 KiB) TX bytes:3946 (3.8 KiB)
Interrupt:225 Memory:da000000-da012100

output of ifconfig eth0 of #2:
eth0 Link encap:Ethernet HWaddr 00:21:5E:22:03:66
inet addr:192.168.168.201 Bcast:192.168.168.255 Mask:
255.255.255.0
inet6 addr: fe80::221:5eff:fe22:366/64 Scope: Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:57 errors:0 dropped:0 overruns:0 frame:0
TX packets:127 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:4139 (4.0 KiB) TX bytes:8853 (8.6 KiB)
Interrupt:17 Memory:da000000-da012100

output of ifconfig eth0 of #3:
eth0 Link encap:Ethernet HWaddr 00:21:5E:22:03:A2
inet addr:192.168.168.201 Bcast:192.168.168.255 Mask:
255.255.255.0
inet6 addr: fe80::221:5eff:fe22:378/64 Scope: Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:97 errors:0 dropped:0 overruns:0 frame:0
TX packets:44 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:6732 (6.5 KiB) TX bytes:3538 (3.4 KiB)
Interrupt:209 Memory:da000000-da012100

output of route -n of #1:
Destination Gateway Genmask Flags Metric Ref
Use Iface
192.168.168.0 0.0.0.0 255.255.255.0 U 0
0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0
0 0 eth0
0.0.0.0 192.168.168.1 0.0.0.0 UG 0
0 0 eth0

output of route -n of #2:
Destination Gateway Genmask Flags Metric Ref
Use Iface
192.168.168.0 0.0.0.0 255.255.255.0 U 5
0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 5
0 0 eth0
0.0.0.0 192.168.168.1 0.0.0.0 UG 5
0 0 eth0

output of route -n of #3:
Destination Gateway Genmask Flags Metric Ref
Use Iface
192.168.168.0 0.0.0.0 255.255.255.0 U 0
0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0
0 0 eth0

On Jan 16, 7:40*pm, fl...@apaflo.com (Floyd L. Davidson) wrote:
> All three machines are configured with the same IP address.

Oops, that was a typo. The IP addresses have been configured to
#1: 192.168.168.201
#2: 192.168.168.202
#3: 192.168.168.203
as I've said.