We have are planning to get for 2Mbps lines from the same ISP(their max).
The lines will have different routers in front of them so they can be
configuered
to be in different networks.
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--Pix Box---------Load Balancer----|------------------
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This is a simplified diagram, I am trying to write the load balancing
rules in pf
This is what i have got so far
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lan_net = "10.7.2.0/24"
int_if = "fxp0"
ext_if1 = "rl0"
ext_if2 = "em0"
ext_if1 = "rl1"
ext_if2 = "rl2"
ext_gw1 = "10.7.3.1"
ext_gw2 = "10.7.4.1"
ext_gw3 = "10.7.5.1"
ext_gw4 = "10.7.6.1"
# nat outgoing connections on each internet interface
nat on $ext_if1 from $lan_net to any -> ($ext_if1)
nat on $ext_if2 from $lan_net to any -> ($ext_if2)
nat on $ext_if3 from $lan_net to any -> ($ext_if3)
nat on $ext_if4 from $lan_net to any -> ($ext_if4)
# default deny
block in from any to any
block out from any to any
# pass all outgoing packets on internal interface
pass out on $int_if from any to $lan_net
# pass in quick any packets destined for the gateway itself
pass in quick on $int_if from $lan_net to $int_if
# load balance outgoing tcp traffic from internal network.
pass in on $int_if route-to { ($ext_if1 $ext_gw1), ($ext_if2 $ext_gw2) \
, ($ext_if3 $ext_gw3), ($ext_if4 $ext_gw4i) } round-robin proto tcp from \
$lan_net to any flags S/SA modulate state
# load balance outgoing udp and icmp traffic from internal network
pass in on $int_if route-to { ($ext_if1 $ext_gw1), ($ext_if2 $ext_gw2), \
($ext_if3 $ext_gw3), ($ext_if4 $ext_gw4i) } round-robin proto { udp, icmp } \
from $lan_net to any keep state
# general "pass out" rules for external interfaces
pass out on $ext_if1 proto tcp from any to any flags S/SA modulate state
pass out on $ext_if1 proto { udp, icmp } from any to any keep state
pass out on $ext_if2 proto tcp from any to any flags S/SA modulate state
pass out on $ext_if2 proto { udp, icmp } from any to any keep state
pass out on $ext_if3 proto tcp from any to any flags S/SA modulate state
pass out on $ext_if3 proto { udp, icmp } from any to any keep state
pass out on $ext_if4 proto tcp from any to any flags S/SA modulate state
pass out on $ext_if5 proto { udp, icmp } from any to any keep state
# route packets from any IPs on $ext_if1 to $ext_gw1 and the same for
# $ext_if2 and $ext_gw2
pass out on $ext_if1 route-to ($ext_if2 $ext_gw2) from $ext_if2 to any
pass out on $ext_if2 route-to ($ext_if1 $ext_gw1) from $ext_if1 to an
As i see the rules are still incomplete after the last to rules.
1. do i need 3 rules for each interface in the end to the total of 12 more rules
2. Would I be better of using bgpd.
I had posted the same problem a couple of years ago with the similar setup.
Then I had to load balance 3 lines. That time i used iptables+iproute2
combination. That wont work in this case, as lartc mentions, iproute2 does
route caching, now if someone access youtube once and lots of users do the
same, the same connection is used by all. which does not suffice for a
solution here
So that is out completely. This time i have to drive this to completion, I dont
want my senior Windows admin to out ISA there. Wish me luck too.
Manpreet
