jet@uh.edu ("J. Eric Townsend") (01/04/91)
I've invented the XOR gateway, can I patent it? :-( Sun 4/60C, 4.0.3c, antares ethernet card. I set up my two ethernet ports with: ifconfig le0 karazm netmask 255.255.0.0 broadcast 129.7.255.255 -trailers ifconfig le1 karazm-rt netmask 255.255.240.0 broadcast 129.7.128.255 -trailers I'm running in.routed, and yp is not being used. As long as le1 is ifconfig'd down, I can talk to anything on the le0 side of the network. If I ifconfig le1 to be up, I can talk to anything on its side, but I can't talk to anything on the le0 side! Grr. Anybody have any sorts of hints or suggestions? Is there perhaps a known bug in the le device driver or some other such nonsense? I'm not going to go to 4.1 unless i *HAVE* to, since there's a cluster of ss-2's on order that will arrive with 4.1.1 (and everything else will get upgraded to 4.1.1 then). J. Eric Townsend Internet: jet@uh.edu Bitnet: jet@UHOU Systems Mangler - UH Dept. of Mathematics - (713) 749-2120 Skate UNIX, boyo. [[Ed's Note: Followup message received. -bdg]] Here's the quick answer: Use the same netmask on each interface. Several people explained this to me. (I don't remember seeing it in the manual. Grr) Here's the explination of *why* you need the same netmasks: From: rjt@sedist.cray.com (Randy Thomas) |Your problem is the netmask. Net 129.7 is assigned to both interfaces, |so they both have to have the same netmask. It has to do with the way |routing code works. | |When a packet is to be sent out, the routing code first looks at each running |interface, picks out the subnet mask on that interface, and then compares the |derived packet subnet against the subnet assigned to that interface (when you |assigned the interface the IP address). If the subnets match, it goes out that |interface. | |Because both interfaces on your machine share the same 'real' net, 129.7, |it is likely that most outbound packets are also destined for 129.7.xx.xx. |When le0 is the only interface up, all traffic has to go out it. Likewise |when le1 is the only running interface. | |When they are both up, however, anything destined for, say, 129.7.128.34, |can go out either interface, because it matches BOTH subnets...and the interface |the kernel chooses, by Randy's Corollary to Murphy's Law, is always going to be |the interface that is not connected to the network you need. | |You can see this via the netstat -i command, and watch the packet counts |when you ping a host. Notice how the counters go up on the 'wrong interface?'