Two interfaces - question

Two interfaces - question

[Marcin Giedz]

Hello,

In my INtel Blade server I have two ethernet interfaces: eth0, eth1. Now only 
one is working, the another one is not configured. However I'd like to have 
something like dynamic routing: if one interfaces is down the second one if 
up. If first returns up the second one goes down. 

Does anyone know how can I do this?

Thx,
Marcin

Re: Two interfaces - question

[vikrant]

Marcin Giedz wrote:

>Hello,
>
>In my INtel Blade server I have two ethernet interfaces: eth0, eth1. Now only 
>one is working, the another one is not configured. However I'd like to have 
>something like dynamic routing: if one interfaces is down the second one if 
>  
>
i am getting little confused when u say interface goes down please 
explain . 
what do u mean from interface does down whether interface card become 
inactive or network cable get damage or ISP connection goes down please 
clarify it .

>up. If first returns up the second one goes down. 
>
>Does anyone know how can I do this?
>
>Thx,
>Marcin
>
>
>
>  
>
Thanks
Vikrant

Re: Two interfaces - question

[Marcin Giedz]

Dnia środa, 4 stycznia 2006 12:16, vikrant napisał:
> Marcin Giedz wrote:
> >Hello,
> >
> >In my INtel Blade server I have two ethernet interfaces: eth0, eth1. Now
> > only one is working, the another one is not configured. However I'd like
> > to have something like dynamic routing: if one interfaces is down the
> > second one if
>
> i am getting little confused when u say interface goes down please
> explain .
OK - very spimle. Let's say that network cable is damage or someone has 
disconnected cable from the card. If one cable is unplagged (eth0) the second 
one (eth1) becames master.


> what do u mean from interface does down whether interface card become
> inactive or network cable get damage or ISP connection goes down please
> clarify it .
>
> >up. If first returns up the second one goes down.
> >
> >Does anyone know how can I do this?
> >
> >Thx,
> >Marcin
>
> Thanks
> Vikrant

Re: Two interfaces - question

[Boryan Yotov]

Marcin Giedz wrote:
> Dnia środa, 4 stycznia 2006 12:16, vikrant napisał:
> 
>>Marcin Giedz wrote:
>>
>>>Hello,
>>>
>>>In my INtel Blade server I have two ethernet interfaces: eth0, eth1. Now
>>>only one is working, the another one is not configured. However I'd like
>>>to have something like dynamic routing: if one interfaces is down the
>>>second one if
>>
>>i am getting little confused when u say interface goes down please
>>explain .
> 
> OK - very spimle. Let's say that network cable is damage or someone has 
> disconnected cable from the card. If one cable is unplagged (eth0) the second 
> one (eth1) becames master.

Check _mii-tool_ from Donald Becker and/or _ifplugd_ from Lennart 
Poettering.

> 
> 
> 
>>what do u mean from interface does down whether interface card become
>>inactive or network cable get damage or ISP connection goes down please
>>clarify it .
>>
>>
>>>up. If first returns up the second one goes down.
>>>
>>>Does anyone know how can I do this?
>>>
>>>Thx,
>>>Marcin
>>
>>Thanks
>>Vikrant
> 
> 
> 
> 

Re: Two interfaces - question

[vikrant]

Marcin Giedz wrote:

>Dnia środa, 4 stycznia 2006 12:16, vikrant napisał:
>  
>
>>Marcin Giedz wrote:
>>    
>>
>>>Hello,
>>>
>>>In my INtel Blade server I have two ethernet interfaces: eth0, eth1. Now
>>>only one is working, the another one is not configured. However I'd like
>>>to have something like dynamic routing: if one interfaces is down the
>>>second one if
>>>      
>>>
>>i am getting little confused when u say interface goes down please
>>explain .
>>    
>>
>OK - very spimle. Let's say that network cable is damage or someone has 
>disconnected cable from the card. If one cable is unplagged (eth0) the second 
>one (eth1) becames master.
>
>
>  
>
>>what do u mean from interface does down whether interface card become
>>inactive or network cable get damage or ISP connection goes down please
>>clarify it .
>>
>>    
>>
>>>up. If first returns up the second one goes down.
>>>
>>>Does anyone know how can I do this?
>>>
>>>Thx,
>>>Marcin
>>>      
>>>
>>Thanks
>>Vikrant
>>    
>>
>
>
>  
>
I am considering that both the interfaces are using as external interface.
I don't  know the right way to track the connectivity ,I think Routing 
Protocol e.g BGP,RIP,IGP or OSPF are the solution for this  kind of  
problem.
But ,what i did to do this ,write a script that ping the ISP DNS  and 
set the status value (variable)according to packet loss % and then take 
action according to the status value , ifdown eth0 -> ifup eth1 -> make 
changes to iptables rules  , and vice-versa.
add the script in crontab so that it runs after a certain time period 
and perform the checking.
I am just a beginner so please do not consider it as the final solution.
Please know me if u find the right ans to ur ques.
and sorry for bad english.

Thanks
Vikrant

Re: Two interfaces - question

[vikrant]

vikrant wrote:

> Marcin Giedz wrote:
>
>> Dnia środa, 4 stycznia 2006 12:16, vikrant napisał:
>>  
>>
>>> Marcin Giedz wrote:
>>>   
>>>
>>>> Hello,
>>>>
>>>> In my INtel Blade server I have two ethernet interfaces: eth0, 
>>>> eth1. Now
>>>> only one is working, the another one is not configured. However I'd 
>>>> like
>>>> to have something like dynamic routing: if one interfaces is down the
>>>> second one if
>>>>     
>>>
>>> i am getting little confused when u say interface goes down please
>>> explain .
>>>   
>>
>> OK - very spimle. Let's say that network cable is damage or someone 
>> has disconnected cable from the card. If one cable is unplagged 
>> (eth0) the second one (eth1) becames master.
>>
>>
>>  
>>
>>> what do u mean from interface does down whether interface card become
>>> inactive or network cable get damage or ISP connection goes down please
>>> clarify it .
>>>
>>>   
>>>
>>>> up. If first returns up the second one goes down.
>>>>
>>>> Does anyone know how can I do this?
>>>>
>>>> Thx,
>>>> Marcin
>>>>     
>>>
>>> Thanks
>>> Vikrant
>>>   
>>
>>
>>
>>  
>>
> I am considering that both the interfaces are using as external 
> interface.
> I don't  know the right way to track the connectivity ,I think Routing 
> Protocol e.g BGP,RIP,IGP or OSPF are the solution for this  kind of  
> problem.
> But ,what i did to do this ,write a script that ping the ISP DNS  and 
> set the status value (variable)according to packet loss % and then 
> take action according to the status value , ifdown eth0 -> ifup eth1 
> -> make changes to iptables rules  , and vice-versa.
> add the script in crontab so that it runs after a certain time period 
> and perform the checking.
> I am just a beginner so please do not consider it as the final solution.
> Please know me if u find the right ans to ur ques.
> and sorry for bad english.
>
> Thanks
> Vikrant
>
>
>
If your problem is just limited to plugin or plugout of cable then u can 
use ifplugd as Boryan yotov suggests but by this u can not check whether 
ISP line in up or down.

link for ifplugd
http://www.stud.uni-hamburg.de/users/lennart/projects/ifplugd/

Re: Two interfaces - question

[Jesus M. Salvo Jr.]

On Wednesday 04 January 2006 22:16, vikrant wrote:
> Marcin Giedz wrote:
> >Hello,
> >
> >In my INtel Blade server I have two ethernet interfaces: eth0, eth1. Now
> > only one is working, the another one is not configured. However I'd like
> > to have something like dynamic routing: if one interfaces is down the
> > second one if
>
> i am getting little confused when u say interface goes down please
> explain .
> what do u mean from interface does down whether interface card become
> inactive or network cable get damage or ISP connection goes down please
> clarify it .
>
> >up. If first returns up the second one goes down.
> >
> >Does anyone know how can I do this?
> >
> >Thx,
> >Marcin
>
> Thanks
> Vikrant

What you are looking for is the bonding driver / interface.
Have a look in your filesystem for the file:

/usr/src/<kernel>/Documentation/networking/bonding.txt