-----Original Message-----
From: Luciano Ruete [mailto:[EMAIL PROTECTED] 
Sent: Saturday, June 02, 2007 11:28 AM
To: Salim S I
Cc: lartc@mailman.ds9a.nl
Subject: Re: [LARTC] Multihome load balancing - kernel vs netfilter

>Is not about ego, sorry if you take this personal, it is not my
intention, >i 
>speak rude because this list get heavly indexed by google, and it is
taked >as 
>good advice for many answer seekers.
>
>You afirm that Linux cannot handle load balancing properly and this is 
>completly WRONG and is bad advertising and a lie. 
>
>Since 2.4 series has been avaible the greats julian's patchs[1], and
then >in 
>2.6.12 CONNMARK has get in mainline, and with a litle of setup all
>connection 
>problems related to load balancing get perfectly solved.


I did not say Linux can't do Load balancing (btw, my setup has Julian's
DGD patch as well as CONNMARK). But there are some limitations to the
popular methods currently used.

1.As Peter Rabbitson [EMAIL PROTECTED] mentioned, one issue is the
separate control and data servers. He mentions AIM servers as example.
This probably can only be solved by having exception IP list. 

2.The other situation, and the one I am more concerned, is about
different connections which belongs to same session.

Consider Client X and Server Y. 

Client X initiates a connection from port a to port b of server Y.

Xa <---> Yb   This connection goes through WAN1.

After sometime, X opens another connection to Y from port c to port d.

Xc <---> Yd   This is a perfectly new TCP connection, so it may go
through WAN2

(Note that the client is NATed, and that no CONNTRACK exist for this
app)

The server may reject the second and subsequent connections as it comes
in with a different source IP than the first.

This situation happens often in IM and Gaming scenarios. Some sort of IP
persistence is required to handle this. And I was wondering if recent
match would solve this to an extent, without affecting performance. Or
if there are some other method available. (Note that I can't depend much
on cache).




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