You can only have one default route statement in any network setup. This is
the route

0.0.0.0/0 --> interface / gateway IP.

If you have 2 such lines in your route table your network will fail almost
every time both interfaces that 0.0.0.0/0 point to become active. The reason
i say almost is because you can use route metrics or preference to specify
which default route is currently active and which one is on standby incase
the other goes down. I use this technique to provide seamless ISP failover
for clients.



On Wed, Feb 23, 2011 at 3:19 AM, Richard Zulu <[email protected]> wrote:

> Well,
>
> The internal interface has a private I.P address, with a default gateway of
> something like 172.16.0.1 and a subnet of /16
>
> The external interfaces have Public I.Ps, with their default gateway having
> public I.P.
>
> @Collins, with the internal interface up, the internal interface has it's
> default route pointing to it's default gateway, 172.16.0.1
>
> And the external interfaces also points to their own default gateway.
>
>
>
> On Wed, Feb 23, 2011 at 2:52 AM, sanga collins <[email protected]>wrote:
>
>> what is your default route when the internal interface is up?
>>
>> On Tue, Feb 22, 2011 at 5:19 AM, Richard Zulu <[email protected]> wrote:
>>
>>> Hi,
>>>
>>> Quick question: I have a linux box with three interfaces,  two of them
>>> face my external network (one is a sub-interface) , with the same gateway
>>> address but obviously different I.Ps. Both are in the same public network /
>>> subnet
>>>
>>> One of the interfaces faces my internal network, private IP addresses.
>>>
>>> Problem: With all the interfaces up, I cannot reach any of the networks,
>>> both internal and external.
>>>
>>> However, with the internal network interface down, I can get to the
>>> external network.
>>>
>>> I need my internal interface up so that I can get to my internal network
>>> and at the same time get to the external networks.
>>>
>>> How can I pull it off?
>>>
>>>
>>>
>>> --
>>> Richard Zulu
>>> gtug lead, Kampala (Uganda)
>>> http://kampala.gtugs.org
>>>
>>>
>>>
>>> _______________________________________________
>>> The Uganda Linux User Group: http://linux.or.ug
>>>
>>> Send messages to this mailing list by addressing e-mails to:
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>>>
>>> The Uganda LUG mailing list is generously hosted by INFOCOM:
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>>>
>>> The above comments and data are owned by whoever posted them (including
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>>>
>>
>>
>>
>> --
>> Sanga M. Collins
>> Network Engineering
>> ~~~~~~~~~~~~~~~~~~~~~~~
>> Google Voice: (954) 324-1365
>> E- fax: (435) 578 7411
>>
>> _______________________________________________
>> The Uganda Linux User Group: http://linux.or.ug
>>
>> Send messages to this mailing list by addressing e-mails to:
>> [email protected]
>> Mailing list archives: http://www.mail-archive.com/[email protected]/
>> Mailing list settings: http://kym.net/mailman/listinfo/lug
>> To unsubscribe: http://kym.net/mailman/options/lug
>>
>> The Uganda LUG mailing list is generously hosted by INFOCOM:
>> http://www.infocom.co.ug/
>>
>> The above comments and data are owned by whoever posted them (including
>> attachments if any). The mailing list host is not responsible for them in
>> any way.
>>
>
>
>
> --
> Richard Zulu
> gtug lead, Kampala (Uganda)
> http://kampala.gtugs.org
>
>
>
> _______________________________________________
> The Uganda Linux User Group: http://linux.or.ug
>
> Send messages to this mailing list by addressing e-mails to:
> [email protected]
> Mailing list archives: http://www.mail-archive.com/[email protected]/
> Mailing list settings: http://kym.net/mailman/listinfo/lug
> To unsubscribe: http://kym.net/mailman/options/lug
>
> The Uganda LUG mailing list is generously hosted by INFOCOM:
> http://www.infocom.co.ug/
>
> The above comments and data are owned by whoever posted them (including
> attachments if any). The mailing list host is not responsible for them in
> any way.
>



-- 
Sanga M. Collins
Network Engineering
~~~~~~~~~~~~~~~~~~~~~~~
Google Voice: (954) 324-1365
E- fax: (435) 578 7411
_______________________________________________
The Uganda Linux User Group: http://linux.or.ug

Send messages to this mailing list by addressing e-mails to: [email protected]
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To unsubscribe: http://kym.net/mailman/options/lug

The Uganda LUG mailing list is generously hosted by INFOCOM: 
http://www.infocom.co.ug/

The above comments and data are owned by whoever posted them (including 
attachments if any). The mailing list host is not responsible for them in any 
way.

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