On Fri, Jun 13, 2003 at 12:16:52PM -0500, Ivan Rodriguez wrote: > Hi > i have the next situation > > ADSL > eth1---------> > 192.168.64.x --->LinuxBox > eth0---------> > DS0 > > my Linux box is a GW i need the following: > > > if etho is down then all traffic is routed > by eth1 and if eth1 is down then all > traffic is routed by eth0 > > it is posible ? Yes, it is possible but not easy. First of all, if a link goes down, so does your MASQ'ed sessions. You just can't switch the masq'ing interface. Secondly, the inbound initiations are totally out of your control. If someone sends you a packet with dst (eth0) and eth0 is down, the packet would be dropped (with an appropriate ICMP generated). I'm sure there are other deficiencies to this setup. One way of setting this up is to have a static IP assigned to a loopback (dummy device in linux terminology) on the linux box and have your ISP's (both if there are two) route that IP to you through your both interfaces. Then you would SNAT everything with that IP and set up your routes (with or without an equal cost) to both interfaces. Unfortunately in home setups the ethX might show up while the link is basically down, which means you have to monitor your next-hop access and remove the unreachable route if necessary, otherwise you'll create a blackhole for yourself. At any rate, you need a static IP and two (or one) willing ISP(s) to route that IP to you... From your routing table below it looks like you have eth1 and ppp0 to the Internet which seem to be on the same /18. So you're one step closer to this solution... Ramin > please help me and excusme mi english is not god > > > Destination Gateway Genmask Flags > MSS Window irtt > Iface > > 148.223.133.227 192.168.65.1 255.255.255.255 UGH > 40 0 0 > eth1 > > 148.223.182.205 0.0.0.0 255.255.255.255 UH > 40 0 0 > ppp0 > > 192.168.65.0 192.168.65.1 255.255.255.0 UG > 40 0 0 > eth1 > > 192.168.65.0 0.0.0.0 255.255.255.0 U > 40 0 0 > eth1 > > 10.0.0.0 0.0.0.0 255.0.0.0 U > 40 0 0 > eth0 > > 127.0.0.0 0.0.0.0 255.0.0.0 U > 40 0 0 > lo > > 0.0.0.0 148.223.182.205 0.0.0.0 UG > 40 0 0 > ppp0
