Re: [LARTC] Need information on multi-homing

[bruce@perens.com (Bruce Perens)]

On Sun, Mar 03, 2002 at 12:16:54PM +0100, bert hubert wrote:
> Right now you are telling the kernel to route packets FROM 216.15.108.186 TO
> 216.15.108.186, which isn't happening :-)

I should have known better than _that_. OK, it works now. Thanks very
much.

>> why not have squid alternate addresses so that receive data is interleaved
>> across the two DSL lines? Wouldn't that balance better than simply routing
>> half of the internet through each interface?
 
> It isn't persistent. Many internet sites rely on the fact that users keep
> coming from the same IP address during their session.

Good point. I don't know how, or if, proxies like squid use persistent
connections. I suspect that some load-balancing schemes already break them.
apt-get (Debian's package downloader) already knows how to parallelize hosts.
It would be nice to parallelize the interfaces at the same time.

FYI, this is a picture of my net.

	768K SDSL ------------------------------------ eth0


	1.5M..384K/128K ADSL ------------------------- eth1
					^
					| (10MBPS)
					|
				Retail Router Box		Linux Box
				Serves local DHCP
				hosts with DHCP, NAT,
				"firewall", gateway.
					^
					|
					|
        Local DHCP net ------------------------------- eth2

All networks are 100/10 MBit full-duplex switches. Both DSL modems and
the uplink port of the retail router run 10 MBit half-duplex, everything
else runs 100 MBit full-duplex. Not much should be going through
the retail router box, as the Linux box serves the local net with squid,
IMAP, SMTP, and telnet. I could dispense with the router box and route
with Linux if I wanted to.

Attached is what I ended up with in /etc/network/interfaces:

	Thanks

	Bruce

auto eth0
iface eth0 inet static
    address 216.15.108.186
    network 216.15.108.184
    netmask 255.255.255.248
    broadcast 216.15.108.255
    # gateway 216.15.108.185
    up ip rule add from 216.15.108.186 table dnai-net 
    up ip route add default via 216.15.108.185 dev eth0 table dnai-net
    up ip route add default via 216.15.108.185 dev eth0 metric 1 table main
    down ip rule del from 216.15.108.186 table dnai-net 
    down ip route del default via 216.15.108.185 dev eth0 table dnai-net
    down ip route del default via 216.15.108.185 dev eth0 metric 1 table main

auto eth1
iface eth1 inet static
    address 67.114.175.138
    network 67.114.175.137
    netmask 255.255.255.248
    broadcast 67.114.175.143
    up ip rule add from 67.114.175.138 table sbc-net
    up ip route add default via 67.114.175.137 dev eth1 table sbc-net
    up ip route add default via 67.114.175.137 dev eth1 metric 2 table main
    down ip rule del from 67.114.175.138 table sbc-net
    down ip route del default via 67.114.175.137 dev eth1 table sbc-net
    down ip route del default via 67.114.175.137 dev eth1 metric 2 table main

auto eth2
iface eth2 inet static
    address 192.168.1.1
    network 192.168.1.0
    netmask 255.255.255.0
    broadcast 192.168.1.255
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