iproute2 load balacing

[n***@tin.it]

hello all,I have doubts about the management of the multipath with iproute2.In particular, do not understand how is the distrubution of traffic between two gateways.Use this command ip route add default scope global nexthop via 192.168.1.1 deveth1 weight 1 nexthop via 10.64.64.64 dev ppp0 weight 1Actually I see that some servers will reach from 192.168.1.1, others from10.64.64.64, but I do not understand the logic that uses this command.Can you help me understand?
Tnx.

[Pascal Hambourg]

Hello,

Post by n***@tin.it
I have doubts about the management of the multipath with iproute2.
In particular, do not understand how is the distrubution of traffic
between two gateways.
Use this command
ip route add default scope global \
nexthop via 192.168.1.1 dev eth1 weight 1 \
nexthop via 10.64.64.64 dev ppp0 weight 1
Actually I see that some servers will reach from 192.168.1.1, others
from10.64.64.64, but I do not understand the logic that uses this command.
Can you help me understand?

iproute multipath does not distribute traffic but routing cache entries.
A routing cache entry is based on the source and destination addresses,
and is used to route all packets matching these until it expires.
It means that all communications from A to B will use the same path
because they use the same routing cache entry. The distribution
algorithm is a simple weighted round robin and does not take the amount
of traffic on each path into account.

The efficiency as a load balancing increases with the number of routing
cache entries, i.e. the number of sources and/or destinations.

[n***@tin.it]

hello, thank you for your response.

Configuring the multipath as I
showed you, I need to split the traffic between the two wan. The
traffic, however, does not come from the LAN, but is degeneratedby the
firewall.

Using this rule:

ip rule add fwmark 3 table 3
ip rule add
fwmark 4 table 4

iptables-t mangle-A OUTPUT-p tcp - dport 25-j MARK -
set-mark 3
iptables-t mangle-A OUTPUT-p tcp - dport 110-j MARK - set-
mark 4

but it also happens that packets coming out from the right
interface but with the ip of the other WAN and viceversa

So I decided
to use SNAT --to ip[eth1] and SNAT --to ip[eth2] ,forcing a correct
routing.

But ,I did not understand why, I must constantly flush the
routing cache otherwise I lose packets and dont work.
Tnx
ninnig


----
Messaggio originale----
Da: ***@plouf.fr.eu.org
Data: 18-mag-
2012 11.30
A: "***@tin.it"<***@tin.it>
Cc: <debian-
***@lists.debian.org>
Ogg: Re: iproute2 load balacing

Hello,

Post by n***@tin.it
I have doubts about the management of the

multipath with iproute2.

Post by n***@tin.it
In particular, do not understand how is

the distrubution of traffic

Post by n***@tin.it
between two gateways.
Use this

command

Post by n***@tin.it
ip route add default scope global \
nexthop via

192.168.1.1 dev eth1 weight 1 \

Post by n***@tin.it
nexthop via 10.64.64.64 dev ppp0

weight 1

Post by n***@tin.it
Actually I see that some servers will reach from

192.168.1.1, others

Post by n***@tin.it
from10.64.64.64, but I do not understand the

logic that uses this command.

Post by n***@tin.it
Can you help me understand?

iproute
multipath does not distribute traffic but routing cache entries.
A
routing cache entry is based on the source and destination addresses,

and is used to route all packets matching these until it expires.
It
means that all communications from A to B will use the same path

because they use the same routing cache entry. The distribution

algorithm is a simple weighted round robin and does not take the amount

of traffic on each path into account.

The efficiency as a load
balancing increases with the number of routing
cache entries, i.e. the
number of sources and/or destinations.