[isp-bgp] BGP Configuration

[John De La Fuente <john@...>]

Hi Everyone,

I have a BGP question that I can't really find the answer to.

We run a number of routers within our network, and have very recently 
introduced BGP. Now, we're running EIGRP to most routers, and RIPv2 to 
those routers that can't run EIGRP. We redistribute the RIPv2 protocol 
into EIGRP.

Now, prior to BGP, we had a static route set in the router that points 
to our transit:

ip route 0.0.0.0 0.0.0.0 Serial4/0

The BGP feed from our transit is a partial feed and the default route. 
We're going to use the partial feed to do stats on potential peers in 
Australia, and the BGP default route for everyone else.

The BGP default route immediately went to 'RIB-failure' because of the 
static 'ip route' in the config (as expected). So, the default route set 
statically was removed, and the BGP default route went to 'candidate'.

The issue, is that EIGRP doesn't have a 'gateway of last resort' set, 
naturally, because there's no redistribution from BGP into EIGRP. I 
haven't configured EIGRP to redistribute into BGP for the obvious reasons.

How can one tell EIGRP to head to a BGP router without redistributing 
BGP into EIGRP or using 'ip route 0.0.0.0 0.0.0.0 Serial4/0 254' to fool 
EIGRP into thinking there's a route out?


All interfaces connected to the BGP capable router work fine, as the 
external Internet is visible through the BGP routing table, however the 
non BGP routers running only EIGRP can't see any route out of the 
network. I don't want to run iBGP on the other routers as their memory 
sizes are limited to about 64MB. Some can't even run bgp.

Shown below is the router configuration (the ones of interest):

router eigrp 24098
redistribute static
network a.b.c.d
network e.f.g.h
<various other networks>
no auto-summary
no eigrp log-neighbor-changes
no eigrp log-neighbor-warnings
!
router bgp 24098
no synchronization
bgp log-neighbor-changes
network a.b.c.d
network e.f.g.h
neighbor external peer-group
neighbor external remote-as TRANSIT-ISP-AS
neighbor external version 4
neighbor external remove-private-AS
neighbor external prefix-list infilter in
neighbor external prefix-list outfilter out
neighbor external route-map ispin in
neighbor external maximum-prefix 65000
neighbor external filter-list 1 out
neighbor TRANSIT-ISP-IP peer-group external
no auto-summary
!
ip classless
ip route 0.0.0.0 0.0.0.0 Serial4/0 254
ip route e.f.g.h 255.255.255.0 Ethernet2/1
(Other static routes for some clients)
ip route a.b.c.d 255.255.255.0 Null0 254
ip as-path access-list 1 permit ^$
!
ip prefix-list infilter seq 5 deny 0.0.0.0/8 le 32
ip prefix-list infilter seq 10 deny 10.0.0.0/8 le 32
ip prefix-list infilter seq 15 deny 127.0.0.0/8 le 32
ip prefix-list infilter seq 20 deny 169.254.0.0/16 le 32
ip prefix-list infilter seq 25 deny 172.16.0.0/12 le 32
ip prefix-list infilter seq 30 deny 192.0.2.0/24 le 32
ip prefix-list infilter seq 35 deny 192.168.0.0/16 le 32
ip prefix-list infilter seq 40 deny 0.0.0.0/0 ge 25
ip prefix-list infilter seq 45 deny 224.0.0.0/3 le 32
ip prefix-list infilter seq 50 deny a.b.c.d/24 le 32
ip prefix-list infilter seq 65 permit 0.0.0.0/0 le 32
!
ip prefix-list outfilter seq 5 permit a.b.c.d/24 le 25
ip prefix-list outfilter seq 5 permit e.f.g.h/24 le 25
!
access-list 5 permit 0.0.0.0
!
!
route-map ispin permit 10
match ip address 5
set weight 200
!
route-map ispin permit 20
set weight 500
!

Many thanks in advance for your assistance.

Kind regards,
John De La Fuente
Etherwave Networks Pty. Ltd.
















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