Simple routing question
 

We use a dual homed CentOS-6.3 host for our Internet gateway router.
Its internal nic (eth1) is configured such that the address
192.168.0.1 is one of its aliases.

# cat /etc/sysconfig/network-scripts/ifcfg-eth1:192BOOTPROTO=none
BROADCAST=192.168.255.255
DEVICE=eth1:192
IPADDR=192.168.0.1
IPV6INIT=no
MTU=""
NAME="LAN - Non-routable"
NETMASK=255.255.0.0
NETWORK=192.168.0.0
ONBOOT=yes
ONPARENT=yes

Internal packets routed to 192.168.209.41 are passing through this
router out onto the network. I am afraid that the reason is not
evident to me and I have been unable to locate an answer.

The primary address for eth1 has the following configuration:

# cat /etc/sysconfig/network-scripts/ifcfg-eth1
BOOTPROTO=none
BROADCAST=""
DEFROUTE=yes
DEVICE=eth1
DOMAIN="hamilton.harte-lyne.ca harte-lyne.ca"
GATEWAY=216.xxx.yyy.53
HWADDR=00:25:90:60:11:8D
IPADDR=216.xxx.xxx.1
IPV4_FAILURE_FATAL=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
MACADDR=""
MTU=""
NAME="LAN Link - eth1"
NETMASK=""
NETWORK=""
NM_CONTROLLED=no
ONBOOT=yes
PREFIX=24
TYPE=Ethernet
UUID=9c92fad9-6ecb-3e6c-eb4d-8a47c6f50c04

What configuration setting am I missing that will cause packets to
192.168.ccc.ddd to stay on the LAN and not try and pass though the WAN
interface?

--
*** E-Mail is NOT a SECURE channel ***
James B. Byrne mailto:ByrneJB@Harte-Lyne.ca
Harte & Lyne Limited http://www.harte-lyne.ca
9 Brockley Drive vox: +1 905 561 1241
Hamilton, Ontario fax: +1 905 561 0757
Canada L8E 3C3

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Simple routing question
 

On Tue, Sep 4, 2012 at 1:34 PM, James B. Byrne <byrnejb@harte-lyne.ca> wrote:
> We use a dual homed CentOS-6.3 host for our Internet gateway router.
> Its internal nic (eth1) is configured such that the address
> 192.168.0.1 is one of its aliases.
>
> # cat /etc/sysconfig/network-scripts/ifcfg-eth1:192BOOTPROTO=none
>> DEVICE=eth1:192
> IPADDR=192.168.0.1
> NETMASK=255.255.0.0
>
> Internal packets routed to 192.168.209.41 are passing through this
> router out onto the network. I am afraid that the reason is not
> evident to me and I have been unable to locate an answer.

That netmask says the interface handles the range from
192.168.0.0-192.168.255.255. Maybe you meant 255.255.255.0?

--
Les Mikesell
lesmikesell@gmail.com
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Simple routing question
 

On Tue, September 4, 2012 14:34, James B. Byrne wrote:
> We use a dual homed CentOS-6.3 host for our Internet gateway router.
> Its internal nic (eth1) is configured such that the address
> 192.168.0.1 is one of its aliases.
>

per: Les Mikesell lesmikesell at gmail.com
Tue Sep 4 15:01:18 EDT 2012

>> # cat /etc/sysconfig/network-scripts/ifcfg-eth1:192BOOTPROTO=none
>> DEVICE=eth1:192
>> IPADDR=192.168.0.1
>> NETMASK=255.255.0.0
>>
>> Internal packets routed to 192.168.209.41 are passing through this
>> router out onto the network. I am afraid that the reason is not
>> evident to me and I have been unable to locate an answer.
>
> That netmask says the interface handles the range from
> 192.168.0.0-192.168.255.255. Maybe you meant 255.255.255.0?

There are presently two subnets on the lan, 192.168.209.0 and
192.168.209.0. I believe that the present netmask is correct in these
circumstances.

--
*** E-Mail is NOT a SECURE channel ***
James B. Byrne mailto:ByrneJB@Harte-Lyne.ca
Harte & Lyne Limited http://www.harte-lyne.ca
9 Brockley Drive vox: +1 905 561 1241
Hamilton, Ontario fax: +1 905 561 0757
Canada L8E 3C3

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Simple routing question
 

On Tue, Sep 4, 2012 at 2:18 PM, James B. Byrne <byrnejb@harte-lyne.ca> wrote:
>
> On Tue, September 4, 2012 14:34, James B. Byrne wrote:
>> We use a dual homed CentOS-6.3 host for our Internet gateway router.
>> Its internal nic (eth1) is configured such that the address
>> 192.168.0.1 is one of its aliases.
>>
>
> per: Les Mikesell lesmikesell at gmail.com
> Tue Sep 4 15:01:18 EDT 2012
>
>>> # cat /etc/sysconfig/network-scripts/ifcfg-eth1:192BOOTPROTO=none
>>> DEVICE=eth1:192
>>> IPADDR=192.168.0.1
>>> NETMASK=255.255.0.0
>>>
>>> Internal packets routed to 192.168.209.41 are passing through this
>>> router out onto the network. I am afraid that the reason is not
>>> evident to me and I have been unable to locate an answer.
>>
>> That netmask says the interface handles the range from
>> 192.168.0.0-192.168.255.255. Maybe you meant 255.255.255.0?
>
> There are presently two subnets on the lan, 192.168.209.0 and
> 192.168.209.0. I believe that the present netmask is correct in these
> circumstances.

If the 192.168.209.x range is connected to this interface, then I
don't think I understand the problem. I thought you were saying those
addresses should not go out this interface.

--
Les Mikesell
lesmikesell@gmail.com
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Simple routing question
 

On 09/04/12 12:18 PM, James B. Byrne wrote:
> There are presently two subnets on the lan, 192.168.209.0 and
> 192.168.209.0. I believe that the present netmask is correct in these
> circumstances.

um, those are both the same? I assume you meant one of them to be
different?

when you say therre are two subnets, whats the mask for those two
'subnets' ? if its /24 (255.255.255.0) then those subnets would not be
able to reach the gateway at 192.168.0.1 without additional routing
information.



--
john r pierce N 37, W 122
santa cruz ca mid-left coast

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Simple routing question
 

On 09/04/12 12:18 PM, James B. Byrne wrote:
> There are presently two subnets on the lan, 192.168.209.0 and
> 192.168.209.0. I believe that the present netmask is correct in these
> circumstances.

um, those are both the same? I assume you meant one of them to be
different?


You are correct. I mistyped.

I have host A with eth0[aaa.bbb.ccc.A] and eth1[192.168.216.A]

I have host B with eth0[aaa.bbb.ccc.B] and eth1[192.168.209.B]

and I have host C as the gateway with eth0 being the WAN and eth1
being the LAN. Eth1 on C has the address [aaa.bbb.ccc.1] assigned to
it and has the alias [192.168.0.1] as well.

I want traffic from 192.168.216.A addressed to 192.168.209.B to go to
eth1 on B. Instead it goes to Eth0 on C where it dies as one would
expect.

I am not terribly familiar with routing so I expect that I am doing
something wrong that is obvious yet invisible to me. This is an
experimental set up so that I can explore these issues before
inflicting them on my unsuspecting users.

--
*** E-Mail is NOT a SECURE channel ***
James B. Byrne mailto:ByrneJB@Harte-Lyne.ca
Harte & Lyne Limited http://www.harte-lyne.ca
9 Brockley Drive vox: +1 905 561 1241
Hamilton, Ontario fax: +1 905 561 0757
Canada L8E 3C3

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Simple routing question
 

James B. Byrne wrote:
>
> On 09/04/12 12:18 PM, James B. Byrne wrote:
>> There are presently two subnets on the lan, 192.168.209.0 and
>> 192.168.209.0. I believe that the present netmask is correct in these
>> circumstances.
>
> um, those are both the same? I assume you meant one of them to be
> different?
>
>
> You are correct. I mistyped.
>
> I have host A with eth0[aaa.bbb.ccc.A] and eth1[192.168.216.A]
>
> I have host B with eth0[aaa.bbb.ccc.B] and eth1[192.168.209.B]
>
> and I have host C as the gateway with eth0 being the WAN and eth1
> being the LAN. Eth1 on C has the address [aaa.bbb.ccc.1] assigned to
> it and has the alias [192.168.0.1] as well.
>
> I want traffic from 192.168.216.A addressed to 192.168.209.B to go to
> eth1 on B. Instead it goes to Eth0 on C where it dies as one would
> expect.
>
> I am not terribly familiar with routing so I expect that I am doing
> something wrong that is obvious yet invisible to me. This is an
> experimental set up so that I can explore these issues before
> inflicting them on my unsuspecting users.
>

could you show the result of the route command on host C?
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Simple routing question
 

On Tue, Sep 4, 2012 at 3:25 PM, James B. Byrne <byrnejb@harte-lyne.ca> wrote:
>
> On 09/04/12 12:18 PM, James B. Byrne wrote:
>> There are presently two subnets on the lan, 192.168.209.0 and
>> 192.168.209.0. I believe that the present netmask is correct in these
>> circumstances.
>
> um, those are both the same? I assume you meant one of them to be
> different?
>
>
> You are correct. I mistyped.
>
> I have host A with eth0[aaa.bbb.ccc.A] and eth1[192.168.216.A]
>
> I have host B with eth0[aaa.bbb.ccc.B] and eth1[192.168.209.B]
>
> and I have host C as the gateway with eth0 being the WAN and eth1
> being the LAN. Eth1 on C has the address [aaa.bbb.ccc.1] assigned to
> it and has the alias [192.168.0.1] as well.
>
> I want traffic from 192.168.216.A addressed to 192.168.209.B to go to
> eth1 on B.

That should happen directly without C's involvement if the netmask is
255.255.0.0 on A and B's eth1 interfaces.

> Instead it goes to Eth0 on C where it dies as one would
> expect.

Why does C have both internet and LAN addresses on the same interfaces?

--
Les Mikesell
lesmikesell@gmail.com
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Simple routing question
 

On 09/04/12 1:25 PM, James B. Byrne wrote:
> I have host A with eth0[aaa.bbb.ccc.A] and eth1[192.168.216.A]
>
> I have host B with eth0[aaa.bbb.ccc.B] and eth1[192.168.209.B]

what are the subnet masks defined on 192.168.216.A and 192.168.209.B ?


> and I have host C as the gateway with eth0 being the WAN and eth1
> being the LAN. Eth1 on C has the address [aaa.bbb.ccc.1] assigned to
> it and has the alias [192.168.0.1] as well.

assuming the answer to my above question is 255.255.255.0, then noone
has a route to this 192.168.0.1 as its in an entirely different
subnet. you can't overlap subnets with different size masks without
creating some serious messes.


> I want traffic from 192.168.216.A addressed to 192.168.209.B to go to
> eth1 on B. Instead it goes to Eth0 on C where it dies as one would
> expect.

there's no route defined to do that, since 192.168.209.B is not in any
network that A has knowlege of. A would need an IP in the B subnet,
and B would need an IP in the A subnet for this to work.

why do you have two seperate LAN subnets? are you running two seperate
LANs ? there have to be some really good reasons before I create
anything this messy.

for instance...

host A with eth0[aaa.bbb.ccc.A] and eth1[192.168.216.A] and eth1[192.168.209.A]
host B with eth0[aaa.bbb.ccc.B] and eth1[192.168.209.B] and eth1[192.168.216.B]

now A can reach B via its eth1 as it now has a route to 192.168.216/24





--
john r pierce N 37, W 122
santa cruz ca mid-left coast

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Simple routing question
 

per: Nicolas Thierry-Mieg Nicolas.Thierry-Mieg at imag.fr
Tue Sep 4 16:42:57 EDT 2012

> could you show the result of the route command on host C?

[root@gway01 ~]# ip route
216.185.64.52/30 dev eth0 proto kernel scope link src 216.185.64.54
10.0.0.0/24 dev eth1 proto kernel scope link src 10.0.0.1
172.16.0.0/24 dev eth1 proto kernel scope link src 172.16.0.1
169.254.0.0/24 dev eth1 proto kernel scope link src 169.254.0.1
192.168.0.0/24 dev eth1 proto kernel scope link src 192.168.0.1
192.0.0.0/24 dev eth1 proto kernel scope link src 192.0.0.1
216.185.71.0/24 dev eth1 proto kernel scope link src 216.185.71.1
169.254.0.0/16 dev eth0 scope link metric 1002
169.254.0.0/16 dev eth1 scope link metric 1003
default via 216.185.64.53 dev eth0


192.168.0.0/24 dev eth1 proto kernel scope link src 192.168.0.1 is
wrong I think, but I cannot figure out what in the configuration file
is causing it.

# cat /etc/sysconfig/networking/devices/ifcfg-eth1:192
BOOTPROTO=none
NAME=""
MACADDR=""
IPV6INIT=no
DEVICE=eth1:192
MTU=""
NETMASK=255.255.0.0
ONPARENT=yes
BROADCAST=192.168.255.255
IPADDR=192.168.0.1
NETWORK=192.168.0.0
ONBOOT=yes

--
*** E-Mail is NOT a SECURE channel ***
James B. Byrne mailto:ByrneJB@Harte-Lyne.ca
Harte & Lyne Limited http://www.harte-lyne.ca
9 Brockley Drive vox: +1 905 561 1241
Hamilton, Ontario fax: +1 905 561 0757
Canada L8E 3C3

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