BGP Advertise and Receive Default Route

Question:

I have built a lab environment with GNS3. Catalyst Switches  I am trying to get a router (#7) to receive a default route from an eBGP peer (router #4 - normal state).  If router 4's default route goes away (something breaks), I want router 7 to then advertise a default route back to router #4.

I can successfully get routing to work if I manually add/remove the network statement from BGP section of router #7.  I would like to change to happen dynamically without my intervention.  Ideas?

Router #7

router bgp 13979

no synchronization

bgp log-neighbor-changes

redistribute connected

redistribute eigrp 304

network 0.0.0.0 ! command that I have to add/remove

neighbor 192.168.47.4 remote-as 65305

neighbor 192.168.47.4 soft-reconfiguration inbound

no auto-summary

Router #4

router eigrp 100

! under normal situations - EIGRP should learn of the default from other networks

redistribute connected

redistribute bgp 65305 metric 4000 1000 255 1 1500

network 192.168.1.0

network 192.168.104.0

no auto-summary

!

router bgp 65305

no synchronization

bgp log-neighbor-changes

network 0.0.0.0

network 4.4.4.4 mask 255.255.255.255

network 10.10.10.10 mask 255.255.255.255

network 192.168.104.0

neighbor 192.168.47.7 remote-as 13979

neighbor 192.168.47.7 allowas-in

neighbor 192.168.47.7 soft-reconfiguration inbound

distance 200 192.168.47.7 0.0.0.0 bgp_in

no auto-summary

Answer:

 You could do conditional default route advertisement??

Like - if a route exists in my routing table, advertise it out. Or if an interface is up advertise it out. (I will need to try this myself too) If anything is negative, stop advertising.

Not too sure if this would be something that would suit your Cisco Catalyst 3560 situation.

http://wiki.nil.com/BGP_default_route

http://hackingcisco.blogspot.co.uk/2011/05/lab-121-bgp-conditional-route.html

http://blog.ioshints.info/2011/09/responsible-generation-of-bgp-default.html