Re: Problems in Dead Gateway Detection / Failover - MultipleISP Links

[Alessandro Ren <alessandro.ren@xxxxxxxxxxxxxxxxx>]

    I bind to the interface IP and connect to 20 different sites or more, the sites are listed in a text file, using the TCP connect in perl.
    Off course, the ip rule tables the the marks in the firewall must be set correcly so you know that the connections are going through the right interface.
    I can share de script, it's a litle complex in its structus, as it depends on some external scripts, but I will try the share and problably get more and better ideas to do the fail over / multi path routing.
    I will prepare and sent a email with it shortly.

    []s.

Shashikant Mundlik wrote:

Hi Ren,

 

Thanks for your help. But how do you check that you reach less than 20 of your sites. (do you mean 20 websites?).

Will you able to share the script?

That will be great help.

 

Thanks and regards,

 

Shashikant Mundlik

 

System Administrator

UBICS, Pune                                        
Phone:  91 20 2729 1004  x 138  
Mobile : 91 9372 044015

 

www.ubics.com

The UB Group

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From: Alessandro Ren [mailto:alessandro.ren@xxxxxxxxxxxxxxxxx]
Sent: Monday, April 17, 2006 7:31 PM
To: smundlik@xxxxxxxxxxxxxx
Cc: manish@xxxxxxxxxxxx; lartc@xxxxxxxxxxxxxxx
Subject: Re: Problems in Dead Gateway Detection / Failover - MultipleISP Links

    I have a script that connects to 20 diferent sites on the port 80 coming from each link interface a have on my linux router.
    If I reach less than 20% of my sites, I assume the link is down and do all the routing and firewall adjustments to make the traffic goes to other routes, removing the problematic link out, setting ip rules, routes in tables and the main multipath default route and commenting in the firewall the MARKs the would go via the link thats down and it also sets QoS and tries to bring the link that is down back UP.
    Althought I've tested with only 3 links, it supports any number of them.
    It's works very nice so far.

    []s.


Shashikant Mundlik wrote:

Hi There,

 

I am also trying to do the same for my network.
I have two links from different ISPs and I want to configure a failover and load balancing Linux router.

 

I am facing same problem here, that how to detect link failure and let Linux box switch the gateway.

 

I know it works when the first gateway is physically down and not reachable. But what to do if my link is up but there is problem at nexthop level and its not routing packets to destination.

 

Please tell me if this can be overcome by setting multipath routing.

 

Another way I can think of doing this is to use a script which will check if the default route is alive every 15 mins and if not it will make changes in routing table and route the packets through different link.

 

I don't know if this is the best way to do this. If any one know how to do this better please share.

 

If you guys thinks this can work, lets help each other to write such scrip.

 

I am new to LARTC and just now started learning it to solve my network problems.

 

Please help me to achieve this.

 

Thanks in advance.

 

Regards,

 

Shashikant Mundlik

Pune, India.

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__________________________________________________

Alessandro Ren

OpServices Luciana de Abreu, 471 - Sala 403 Porto Alegre, RS - CEP 90570-060

(   phone 55(51)3061-3588 4    fax 55(51)3061-3588

Q   mobile 55(51)8151-8212 :   email alessandro.ren@xxxxxxxxxxxxxxxxx

__________________________________________________

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__________________________________________________

Alessandro Ren

OpServices Luciana de Abreu, 471 - Sala 403 Porto Alegre, RS - CEP 90570-060

(   phone 55(51)3061-3588 4    fax 55(51)3061-3588

Q   mobile 55(51)8151-8212 :   email alessandro.ren@xxxxxxxxxxxxxxxxx

__________________________________________________

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