Hello,

I started off by reading the Linux Advanced Routing & Traffic Control Howto, 
then searched a bit around the web.
I see many documents discussing these matters with kernel 2.2.x but they are 
quite old, something around 1998-2000.

I have some questions but I might as well start by exposing my setup to clarify 
things.

I have a couple of internet links: a leased line of 256kbit/s and an ADSL line 
of 1024kbit/s.
The machine that currently manages them is a win2k3 server with MS ISA server 
2k4 but it doesn't makes any kind of load balancing, we just determine that 
smtp traffic goes one way, the rest goes the other way and divided the vpn's 
load between the links using respective ip addresses.

Not a very bright setup, but it works.
I am trying to get more from these resources and I know that linux or BSD are a 
better choice for this end than win2k3 + ISA. Just to make an example of the 
current limitations, I can't make packet filters redirect traffic, it just 
flows away through the win2k3 default gateway. I can block it though.

                                                                                
  +------------------+
                      \                                                         
  |router 256kb/s    |---- /
                       \                                                        
 /+------------------+    /
                        \     +--------------------+              
*------------*/                        /
      internal network  *-----| win2k3 + MS ISA 2k4|------+-------|Linux 
router|                        |    Internet
                        /     | firewall + Proxy   |      |       |            
|                        |
                       /      +--------------------+      |       
*------------*\                        \
                      /                                   |                     
 \+------------------+    \
                                                          |                     
  |router 1024kb/s   |---- \
                                                          |                     
  +------------------+
                                                        +----------+
                                                        |Mail Relay|
                                                        +----------+

Now from the beginning:

What kernel is the most appropriate for this job? I'm thinking of the lastest 
2.4.x or the 2.6.11 now that it is officially 'all bug free'.

By reading the howto I found one example that's clearly what I have: 
http://lartc.org/howto/lartc.rpdb.multiple-links.html

Since I only have ip space from one of the providers, I will have to masquerade 
for the other.
If I based myself on this example, I would have the outbound routing solved.
But then again what about inbound traffic?! Would I have to do something like 
round robin dns to give me some advantage or is there a more efficient way of 
make it happen? Round robin DNS doesn't know what link is more 'available', I 
mean has more bandwidth available, if DNS was the solution maybe with some way 
of adapting the replyes to the requests dinamically by giving the appropriate 
ip address according to the bandwidth. Even so, it would be nasty because it 
would be cached in DNS servers all over the world...making all the work of 
making it happen useless.
I know nothing on routing protocols like OSPF or even RIP, just a basic 
understanding that they exist and make routing something we all can live with. 
Would I take advantage of them? Would it be secured?

Now for traffic shaping... I will address this later.


What other documentation should I read to get a grip on this?
Recommendable setup, useful docs, thoughts, ideas... Any contribution would be 
gladly appretiated!



Jo�o Carneiro
Departamento de Sistemas e Tecnologias da Informa��o
[EMAIL PROTECTED]


DLS - Projectos Automa��o e Manuten��o, Lda
Tel.: 227 470 786 :: Fax: 227 470 787

-
To unsubscribe from this list: send the line "unsubscribe linux-net" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to