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ralphmt
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using static routes to overide BGP and OSPF internally

Mon May 29, 2023 8:59 am

We have a remote location with "intermittent fiber service" yeah i know what is intermittent fiber service, well its from a provider that has unstable infrastructure in this rural location (best way to put it). We have a CCR1009 on v7.91 (we've tried all sorts of versions) and cannot get the tunneled paths to stay up for manual fail over.

the primary fiber connection is run and is BGP
the secondary Connection is a Spectrum cable modem (dynamic IP Dynamic DNS)
new secondary connection is a 1Gb AT&T ABF fiber/to copper connection. Static IP

As a general rule the fiber path is which is a layer 2 connection to our datacenter runs BGP to our core cisco router directly
our two secondary paths run multihop BGP with the Core Cisco router via a EOIP tunneled connection (we have tried EOIP and GRE and Wireguard tunnels etc, with no change in performance)

the tunnels come up instantly and are stable tunnels, Each tunnel has a static route for the tunneled block to force the traffic out either spectrum or AT&T networks.
Since we have unstable fiber (takes regular errors etc) when it is bad we force the traffic to one connection or another (yes i know we can do this with Med's or preferences, but that gives lower level techs the ability to turn a minor outage into a big deal) so we choose to pre build two static routes in and leave them disabled so all they have to do is enable the route (at each end) and the traffic should flow. and them myself or the lead tech can deal with failing back during normal working hours (ha!)

With that said. the BGP default route, yes we export a default route only to the remote location, shows up with a distance of 15 and the static routes are preconfigured with a 5 and 6 distance respectively.

If I put a static route 0.0.0.0/0 to the far end tunnel address on the ATT circuit the router immediately drops the two tunnels and they cycle 1 sec. down, 1 sec up 1 sec. down etc and the tunnels are unusable. If i put a 0.0.0.0/1 route, everything works fine (except we are missing 1/2 of the internet). I am at a loss for why this behavior happens. the ATT and Spectrum modems are both directly connected to the tik on ports 3 and 4 and the directly connected route (distance 0) should be persistent and not affected by a static route override

Any thoughts on this problem would be appreciated. Its baffled me and my lead tech for about a week now so hopefully the collective brain trust can shine some light on my problem.

Ralph
 
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Buckeye
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Re: using static routes to overide BGP and OSPF internally

Mon May 29, 2023 9:10 am

If I put a static route 0.0.0.0/0 to the far end tunnel address on the ATT circuit the router immediately drops the two tunnels and they cycle 1 sec. down, 1 sec up 1 sec. down etc and the tunnels are unusable. If i put a 0.0.0.0/1 route, everything works fine (except we are missing 1/2 of the internet).
Is the far end tunnel endpoint on ATT in 128.0.0.0/1? (the other half not matched by 0.0.0.0/1).
Last edited by Buckeye on Mon May 29, 2023 9:11 am, edited 1 time in total.
 
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mrz
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Re: using static routes to overide BGP and OSPF internally

Mon May 29, 2023 9:11 am

By routing everything over the tunnel you are routing also tunnel control packets over the tunnel itself making a loop. You need static route to the tunnel endpoint.
 
wiseroute
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Re: using static routes to overide BGP and OSPF internally

Tue May 30, 2023 4:45 am

[*]
static route 0.0.0.0/0 to the far end
[*]

I'm sorry I don't quite understand your layout.

do you mean:
you want to re-route all those connected tunnels back to you as well - just for the tunnels network go to the internet?

you lost half? maybe some kind of unconnected tunnels safe those networks from loops?🤔
 
ralphmt
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Re: using static routes to overide BGP and OSPF internally

Tue May 30, 2023 7:32 am

If I put a static route 0.0.0.0/0 to the far end tunnel address on the ATT circuit the router immediately drops the two tunnels and they cycle 1 sec. down, 1 sec up 1 sec. down etc and the tunnels are unusable. If i put a 0.0.0.0/1 route, everything works fine (except we are missing 1/2 of the internet).
Is the far end tunnel endpoint on ATT in 128.0.0.0/1? (the other half not matched by 0.0.0.0/1).

Far end is in 198,147.x.x so outside of the 0.0.0.0/1 route.
Near end is in 104.x.x.x inisde the routing table the endpoint network is 104 is in the 0.0.0.0/0 however, shows as an DAC route time with a distance of 0 so in normal routing that route should never be overridden by a less specific default route with a distance of 15, right?
 
ralphmt
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Re: using static routes to overide BGP and OSPF internally

Tue May 30, 2023 7:42 am

[*]
static route 0.0.0.0/0 to the far end
[*]

I'm sorry I don't quite understand your layout.

do you mean:
you want to re-route all those connected tunnels back to you as well - just for the tunnels network go to the internet?

you lost half? maybe some kind of unconnected tunnels safe those networks from loops?🤔
Well main fiber is a Layer2 connection and the others are EOIP or GRE tunnels back to the core. There internet comes from the core via BGP to the layer 2 connection and separate peers to the two tunnels. endpoints. the tunnels (as GRE/EOIP) are have there own separate endpoint IP's and the default route will go to the host far end tunnel address. When i wish to NOC staff to steer the traffic it would be a static 0.0.0.0/0 to the core tunnel endpoint address. the same situation exists of the far end router(also a tik) where the move the static's to shove the traffic.
 
ralphmt
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Re: using static routes to overide BGP and OSPF internally

Tue May 30, 2023 7:48 am

By routing everything over the tunnel you are routing also tunnel control packets over the tunnel itself making a loop. You need static route to the tunnel endpoint.
There is already a static route for the endpoint of the tunnel it is set as a 198.x.x.x/32 as well as a default route sent to the far end endpoint of the addresses assigned to the tunnel.
 
wiseroute
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Re: using static routes to overide BGP and OSPF internally

Tue May 30, 2023 9:01 am

@ralphmt

have you really solved the problem? 🤔
 
ralphmt
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Re: using static routes to overide BGP and OSPF internally

Tue May 30, 2023 11:20 pm

@ralphmt

have you really solved the problem? 🤔
nope it is not solved. not sure how it got marked "solved" i guess i must have clicked the wrong button last night (it was late)

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