Difference between revisions of "Source based routing"
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m (Added some info that helped me recently) |
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<pre> | <pre> | ||
# /sbin/ip rule add from $IP table $TBL | # /sbin/ip rule add from $IP table $TBL | ||
| − | # /sbin/ip route add default dev | + | # /sbin/ip route add default dev $ETH via $GW table $TBL |
| + | # /sbin/ip route add $NET dev $ETH table $TBL | ||
| + | |||
</pre> | </pre> | ||
| − | where | + | where |
* <code>$IP</code> is an IP address which should use non-default gateway. You can also use netmask here, e.g. <code>10.9.8.0/24</code> will mean that all containers with addresses like 10.9.8.x will be routed through the given gateway. | * <code>$IP</code> is an IP address which should use non-default gateway. You can also use netmask here, e.g. <code>10.9.8.0/24</code> will mean that all containers with addresses like 10.9.8.x will be routed through the given gateway. | ||
| + | * <code>$NET</code> is an IP network which should be routed straight, that is, not through the gateway. E.g. <code>10.9.8.0/24</code>. | ||
| + | * <code>$ETH</code> is the network interface to route to, e.g. <code>eth0</code>. | ||
* <code>$GW</code> is a gateway for this IP address. | * <code>$GW</code> is a gateway for this IP address. | ||
* <code>$TBL</code> is any free table number, I use numbers from 6 upwards. Note that tables 250-255 are usually reserved (see <code>/etc/iproute2/rt_tables</code>). | * <code>$TBL</code> is any free table number, I use numbers from 6 upwards. Note that tables 250-255 are usually reserved (see <code>/etc/iproute2/rt_tables</code>). | ||
Revision as of 12:01, 16 April 2008
Sometimes you have more than one router in your network, and want different containers to use different routers. For that, you need to set up source-based routing on the host system. For example:
# /sbin/ip rule add from $IP table $TBL # /sbin/ip route add default dev $ETH via $GW table $TBL # /sbin/ip route add $NET dev $ETH table $TBL
where
$IPis an IP address which should use non-default gateway. You can also use netmask here, e.g.10.9.8.0/24will mean that all containers with addresses like 10.9.8.x will be routed through the given gateway.$NETis an IP network which should be routed straight, that is, not through the gateway. E.g.10.9.8.0/24.$ETHis the network interface to route to, e.g.eth0.$GWis a gateway for this IP address.$TBLis any free table number, I use numbers from 6 upwards. Note that tables 250-255 are usually reserved (see/etc/iproute2/rt_tables).
Note that every new non-standard gateway will require another table number.
For more details on routing rules, see man ip.
