RE: backup static routes for freebsd (default)
Thanks Phil, I tried some guesswork myself to add the secondary default routes router style with weights and that's the only way the route add command will accept another default route. I do not know how freebsd interpretes this: route add default [gateway] [administrative weight] though this has no effect when i birng down the default route. Maybe a script to ping the gateways at intervals will do. Any other ideas are welcome. Thanks. Ezra Banoba Systems Administrator/Programmer Computer Froniters International Plot 32 Lumumba Avenue www.cfi.co.ug +256 031260485 -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Philip Payne Sent: Tuesday, August 05, 2003 2:38 AM To: 'Ezra Banoba'; [EMAIL PROTECTED] Subject: RE: backup static routes for freebsd (default) Hi, > I have a gatway box running freebsd 4.8 and several links to > the internet > via different ISP's. > This box is connected directly to one of the ISP's but also > has access to > the other gatways via the LAN. > I would like to setup static backup (default) routes such > that when and if > the main link goes down, the default route for this box is > automatically > changed to point to another router on the LAN.I am having trouble > implementing this on freebsd. > Any ideas? First, I'm more of a router person than familiar with how FreeBSD calculates it's routing table so the following is all guesswork from "man route". The issue with static routes is that they rarely have any idea of the status of their destination but this can be fudged if you're using point-to-point interfaces e.g. DSL, leased line. In general terms what you'd be doing on a router is: 1) Have a default route directed out a point-to-point interface connected to the ISP (not the IP address) so that when the interface is down, the static route is removed from the live routing table. 2) Have a weighted default route via an alternative IP address. The weight implies this route is only used when the former default route is not available. I've read "man route" and I get the impression you can add a route via an interface rather than a destination with the switch "-interface" so your first step is to add a default route along the lines > route add default -interface ... this is a guess as the man page isn't explicit. Also, I don't know whether this route remains live or is removed as required during a failure on the point-to-point interface you'd configure this to. It definitely won't work if your primary access method is a broadcast interface e.g. ethernet. Further, I can't find any details on adding a weight to a static route to create the secondary route so I'm not sure this is going to be possible via an automatic routing table kind of thing. So.(getting to the point very slowly) The only other method I can think of would be a script to ping the far end addresses regularly in order. Depending on which one is up, you could inject a default route statement as required to the correct destination. I'd be interested in other suggestions as this doesn't sound entirely great as there are many other reasons than link failure why an address wouldn't be pingable. Thanks, Phil. ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]" ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
RE: backup static routes for freebsd (default)
Hi, It works like magic. But then, ... that means I still would have to use a script to mark the interface as down when the remote gateway is inaccessible. Or is there a way to automagically mark the interface down if the network is inaccessible? Ezra Banoba Systems Administrator/Programmer Computer Froniters International Plot 32 Lumumba Avenue www.cfi.co.ug +256 031260485 -Original Message- From: Philip Payne [mailto:[EMAIL PROTECTED] Sent: Wednesday, August 06, 2003 1:56 AM To: Nick Rogness; Ezra Banoba Cc: Philip Payne Subject: RE: backup static routes for freebsd (default) Hi, > # route add 0.0.0.0 PRIMARY_GW -netmask 127.0.0.0 > # route add 127.0.0.0 PRIMARY_GW -netmask 127.0.0.0 > # route add default SECONDARY_GW Good thinking, more specific routes take precedence over less specific ones, you always forget the fundamental stuff ;-) ... and it's a routing only solution so no scripts, great. Unfortunately I'm not in a position to try it so, Ezra, if it works let me know for future reference. Would much appreciate it. Thanks, Phil. ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: backup static routes for freebsd (default)
hi, On Mon, Aug 04, 2003 at 11:52:54PM -0700, Ezra Banoba wrote: > Hello, > I have a gatway box running freebsd 4.8 and several links to the internet > via different ISP's. > This box is connected directly to one of the ISP's but also has access to > the other gatways via the LAN. > I would like to setup static backup (default) routes such that when and if > the main link goes down, the default route for this box is automatically > changed to point to another router on the LAN.I am having trouble > implementing this on freebsd. > Any ideas? you might want to take a look at the ng_one2many(4) manpage. It is a module for the netgraph(4) subsystem which allows routing over several links. If you want a really cheap & dirty solution, you could simply write a script that checks if the main gateway is down and then changes the default route to your backup router. hope that helps... ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
RE: backup static routes for freebsd (default)
Hi, > I have a gatway box running freebsd 4.8 and several links to > the internet > via different ISP's. > This box is connected directly to one of the ISP's but also > has access to > the other gatways via the LAN. > I would like to setup static backup (default) routes such > that when and if > the main link goes down, the default route for this box is > automatically > changed to point to another router on the LAN.I am having trouble > implementing this on freebsd. > Any ideas? First, I'm more of a router person than familiar with how FreeBSD calculates it's routing table so the following is all guesswork from "man route". The issue with static routes is that they rarely have any idea of the status of their destination but this can be fudged if you're using point-to-point interfaces e.g. DSL, leased line. In general terms what you'd be doing on a router is: 1) Have a default route directed out a point-to-point interface connected to the ISP (not the IP address) so that when the interface is down, the static route is removed from the live routing table. 2) Have a weighted default route via an alternative IP address. The weight implies this route is only used when the former default route is not available. I've read "man route" and I get the impression you can add a route via an interface rather than a destination with the switch "-interface" so your first step is to add a default route along the lines > route add default -interface ... this is a guess as the man page isn't explicit. Also, I don't know whether this route remains live or is removed as required during a failure on the point-to-point interface you'd configure this to. It definitely won't work if your primary access method is a broadcast interface e.g. ethernet. Further, I can't find any details on adding a weight to a static route to create the secondary route so I'm not sure this is going to be possible via an automatic routing table kind of thing. So.(getting to the point very slowly) The only other method I can think of would be a script to ping the far end addresses regularly in order. Depending on which one is up, you could inject a default route statement as required to the correct destination. I'd be interested in other suggestions as this doesn't sound entirely great as there are many other reasons than link failure why an address wouldn't be pingable. Thanks, Phil. ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: backup static routes for freebsd (default)
On Wed, Aug 06, 2003 at 07:53:55AM -0700, Ezra Banoba wrote: > Hi, > It works like magic. > But then, ... that means I still would have to use a script to mark the > interface as down when the remote gateway is inaccessible. Or is there a way > to automagically mark the interface down if the network is inaccessible? Dynamic routing protocols, such as provided by zebra/quagga? On a multi-access link, determining that the network is down is somewhat difficult unless you can build some kind of keep-alive state-checking mechanism (which is one of the functions that most routing protocols provide). -T -- One day someone asked Master Yun-men: "I've heard it said that one should not leave home to become a monk without parents' consent. How then should one leave home?" "Shallow!" the Master said. "I don't understand." "Deep!" replied the Master. Master Yun-men ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
RE: backup static routes for freebsd (default)
On Tue, 5 Aug 2003, Ezra Banoba wrote: > Thanks Phil, I tried some guesswork myself to add the secondary default > routes router style with weights and that's the only way the route add > command will accept another default route. I do not know how freebsd > interpretes this: route add default [gateway] [administrative weight] > > though this has no effect when i birng down the default route. > > Maybe a script to ping the gateways at intervals will do. Any other > ideas are welcome. Thanks. The trick to adding a backup default route is to split 'default' into 2 different and more specific subnets: # route add 0.0.0.0 PRIMARY_GW -netmask 127.0.0.0 # route add 127.0.0.0 PRIMARY_GW -netmask 127.0.0.0 # route add default SECONDARY_GW Now that default is split into 2 different smaller subnets than 'default' they will be the preferred route. If your interface that connects PRIMARY_GW goes down, the first 2 routes will be removed, leave your backup 'default' gateway to take affect. This only works if PRIMARY_GW and SECONDARY_GW are on seperate physical networks and will also only work if the INTERFACE goes down. It will not work if the PRIMARY_GW goes down but the physical interface connected to that network stays up. Nick Rogness <[EMAIL PROTECTED]> - How many people here have telekenetic powers? Raise my hand. -Emo Philips ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
RE: backup static routes for freebsd (default)
On Wed, 6 Aug 2003, Ezra Banoba wrote: > Hi, It works like magic. But then, ... that means I still would have to > use a script to mark the interface as down when the remote gateway is > inaccessible. Or is there a way to automagically mark the interface down > if the network is inaccessible? Not without a active routing protocol like OSPF/RIP/etc (using gated or zebra). In which case, the interface stays up but the routes get removed. Nick Rogness <[EMAIL PROTECTED]> - How many people here have telekenetic powers? Raise my hand. -Emo Philips ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
backup static routes for freebsd (default)
Hello, I have a gatway box running freebsd 4.8 and several links to the internet via different ISP's. This box is connected directly to one of the ISP's but also has access to the other gatways via the LAN. I would like to setup static backup (default) routes such that when and if the main link goes down, the default route for this box is automatically changed to point to another router on the LAN.I am having trouble implementing this on freebsd. Any ideas? Ezra Banoba Systems Administrator/Programmer Computer Froniters International Plot 32 Lumumba Avenue www.cfi.co.ug +256 031260485 ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
