The problem is that I do not really use gateways in this setup. It is possible that I do have static routes but no default gateways. These are "point-to-point" PPP connections. I guess I screwed up when I said "metric" and "route" in the same sentence. What I meant to say was "metric" and "interface" it may be the same though. Here is my if-up and if-down programs that are ran by pppd after LCP packets are negotiated successfully. The comments explain exactly why we use that program and what it does. I run pppd with the demand option on the remote and on the server. The both have the same address so when the server dials the remote the device ends up with 2 ppp interfaces with the same addresses after LCP negotiation. To keep packets moving if-up downs the other interface and when the link dies if-down ups the one that was taken down. Code: http://demo.opsdc.com/bidir.c You could write the same thing in Perl or whatever but our device does not have the luxury of running scripting languages. What I would like to do is throw in a 3rd PPP interface. The 3rd being vtun using PPP. We use vtun now but not with this demand concept. I might just need to setup my test bed again and see if I can have any luck. Feel free to use the code. Modify or enhance. Send me back anything that needs fixing. Chris On, 2007-07-04 at 19:41 -0400, Bill Davidsen wrote: > Christopher Fowler wrote: > > On Tue, 2007-07-03 at 16:25 -0400, Charlie Brady wrote: > > > >> Google for "linux policy routing" and/or go to > >> http://www.policyrouting.org/ and http://artc.org/howto/. > >> > > > > This brings up a question in regards to something I tried a few years > > ago. Is there a way to use metrics on the routes? > > > > > That's a good question, and the answer is "sort of." I was setting the > defaults like this: > > RPolicy1="src ${ext_p_IP} via ${ext_p_gate} dev ${ext_i1}" > ip route add default ${RPolicy1} metric 2 table mail.in > > (assume I have set the values in the script above, ext_p_IP is the > static IP, etc. Then I set the route which is fast and sheap but uses > DHCP for the IP: > > RPolicy2="via ${ext_s_gate} dev ${ext_s_nic}" > ip route add default ${RPolicy2} metric 1 > > where the secondary IP comes from IPfromNIC after the DHCP has been started. > > I have system that use demand mode PPP to communicate between the server > > and them. the if-up and if-down script actually looks for the other ppp > > interface and takes it down. I wanted to use vtun that uses pppd and > > then only use the modem when the tunnel was down. All my attempts > > failed and everything pointed to me needing to use metrics. > > > > I did some diddling with this back when I still had a fallback to dial, > through an ISP who would give me a static IP. I had a somewhat similar > setup, and had the dial line set to "demand" startup. I gave it up, the > incoming mail melted even bonded modems. > > Anyway, the important thing is that the setup above doesn't work, the > metric gets lost off the "metric 2" setting. However, if I set it with > the old route command "route add default gw x.x.x.x dev eth1 metric 2" > it sets and stays set. I haven't chased that part yet, I'm fighting the > original problem, and it really only matters if the fast NIC goes down. > - To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
