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iproute2: policy routing slowing down existing network?

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http://serverfault.com – I'm using iproute2 to set up policy routing as follows: echo 200 $table >> /etc/iproute2/rt_tables ip rule add from $my_ip table $table ip route add default via $gw_ip dev $dev table $table ip route flush cache Where $dev is a device set-up by OpenVPN. This way everything bound to $my_ip, would go through $gw_ip. This works out fine, except that it seems to slow down the main table's default route traffic, even though there is no traffic at all on the newly set-up route. Is this possible? And if so, how? (HowTos)

taskli's picture
Submitted by taskli on 04/16/2012 – Made popular on 04/16/2012

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I was trying to capture localhost traffic with Ethereal, which doesn't work without re-routing localhost traffic to your router gateway. I didn't get the route command quite right, and messed up my routing table. I typed route -f to clear the routing table and rebooted, but when I finished rebooting, the routing table wasn't restored to its original state.

This is very much a learning question if someone would be happy to explain a couple of concepts.

Ranmaru wrote:I think the problem is that NetworkManager generally prefers ethernet over WiFi and thus tries to route all traffic through eth0 as soon as you connect the cable.I guess you could fix it by using your routing table to prefer the wireless connection over ethernet, but then you would have the problem the other way around.

Hi,

I've created a script in /etc/network/if-up.d/my_script so that when an interface gets up, it creates a new routing table (and deletes it when the interface goes down):

Here is the script:

Code: echo "Setup routing table \"$IFACE\" for address \"$IF_ADDRESS\", gateway \"$IF_GATEWAY\""

ip rule add from $IF_ADDRESS table $IFACE

# cree la

Linux ip route description 38 weeks 6 hours ago

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port redirection through a VPN 1 year 22 weeks ago

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