Nit, Your thinking and that's good!
I'm not sure if you see the whole picture though. route table: (using cisr for brevity 255.255.255.255= /32 255.255.255.0 =/24) 192.168.1.1/32 if0 192.168.1.2/32 if1 192.168.1.3/32 if1 default 192.168.1.4/32 if0 ifconfig: if0 inet 192.168.1.1/32 if1 inet 192.168.1.2/32 Remember: any address/subnet mask set in ifconfig will be added as a route in the route table. Example: if0 encounters a packet for 192.168.1.3. The mask on if0 tells the ip stack that 192.168.1.3 is not in if0's network so it forwards it to the route code. The route table says 'forward to if1.' If1 encounters a packet for 192.168.1.3. Since the mask if1 tells the ip stack that 192.168.1.3 is not in the same network as if1, it will get sent back to the routing code and the packet never gets to the laptop. Ask your self this: what happens when the network information on a host doesn't match the network information in it's gateway? What happens when you assign a /32 subnet mask to a host? nit etc wrote: > --- Kevin Holmquist <[EMAIL PROTECTED]> wrote: > > Nit, > > > > When you say subnet, are you referring to a > > subnetted address block or > > the subnet mask? > > > > Two subnets can have the same mask yet they are > > different subnets, or > > networks. > > > > Routing, by definition, is between networks. A > > basic route table entry > > looks like this: > > > > network address ->mask->interface to forward to > > (please, no flames about > > weighted routes, flags, metrics, etc : )) > > > > The two routes your suggesting would look like this > > example: > > > > 192.168.0.0 255.255.255.0 if0 > > 192.168.0.0 255.255.255.0 if1 > > I was suggesting routing between two different > networks with the same mask. > > 192.168.0.0 255.255.255.0 if0 > 10.0.0.0 255.255.255.0 if1 > > > So where do packets for 192.168.0.247 go? The > > router has two valid > > routes and results would be unpredictable. > > > > If you're thinking about a route entry for a single > > host: > > > > 192.168.0.0 255.255.255.0 if0 > > 192.168.0.247 255.255.255.255 if1 > > I was suggesting the following: > 192.168.1.1 255.255.255.255 eth0 > 192.168.1.2 255.255.255.255 eth1 > 192.168.1.3 255.255.255.255 eth1 > default 192.168.1.4 eth0 > > where 192.168.1.4 is Verizon's gateway, 192.168.1.1,2 > are NICs on my Linux box where 192.168.1.2 is > connected to a hub on my internal network, and > 192.168.1.3 is a laptop. > > When the gateway receives a packet for 192.168.1.2 or > 192.168.1.3 eth0, it puts it on eth1 after looking at > the routing table, so the above wouldnt require my > gateway to run RIP since Im statically assigning the > routes, and dont have a block of IPs to route traffic > between, and because routing information wont change > for me. I am aware that this is not how 'hosts' work, > but a kernel configured to act as a 'gateway' or > 'router' must do the above; else all that I have > learnt in my graduate network course is false ;) > > > > > This doesn't work because broadcast traffic (traffic > > to 192.168.0.255) > > would either never get to 192.168.0.247 or the > > router would see two > > valid routes. > > In my table above, the broadcast traffic will goto all > hosts 192.168.1.1, 192.168.1.2, 192.168.1.3, except to > the one generating the brodcast, but it will not be > put on the eth0 wire, since that is against an RFC > whose number I cant recall(this makes sense, since > otherwise there would be a 'broadcast loop'). > > > > Clear as mud yet? :) > > > > nit etc wrote: > > > > <snip> > > > > > > > > > > > I dont see why I would require two different > > subnets. > > > Gateways can definetly be configured to route > > traffic > > > between > > > two networks with identical subnets. > > > > > > However, in my case, I do believe that things will > > > work if both my NICs have an IP from Verizon, and > > I > > > could add static routes for them with the mask of > > 32. > > > The only problem is getting my other machines to > > > obtain an IP via DHCP. > > > > > > > <snip> > > > > > > > > _______________________________________________ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
