From: EA Louie (elouie@xxxxxxxxx)
Date: Fri Nov 16 2001 - 12:29:59 GMT-3
And.. Thekkathalla... learn to use traceroute. It is one of THE most
important tools that you have for diagnosing routing problems, and it will
definitely tell you where your pings are failing... an incredibly great tool
for troubleshooting your own configurations, especially in the lab. To the
rest of the gang - I can't emphasize how important it is that we see the
results of a trace, because otherwise, we're just guessing about the
problem, although with the collective experience and the description given,
it's easy to *conclude* what we've concluded.
Also, in deference to the other replies, AS1 *probably* does not have a
route back to the serial/LAN interface on AS4 that connects to AS3. That is
why the backwards traceroute is so important. It doesn't matter what the
bgp update source is - a ping uses the address of the outbound interface
(according to the route chosen to the destination). If that outbound
interface subnet is not in the routing/bgp table, your pings won't get
returned. If that's a problem then fix it. That exercise is left to the
reader.
If this is a lab environment, debug ip icmp on AS4 - you'll learn a lot from
what you see (and don't see). View it first to a destination that you CAN
reach, then see it from a destination you CAN'T reach, and compare the
results.
If you're telnetted into the router, remember to type term mon so the
results of the debug are displayed on the router.
If you're connected to console, be sure that logging console is enabled.
good luck - show us your results
-e-
----- Original Message -----
From: "Perminder Grewal" <percy_gunner@hotmail.com>
To: <thek@mediaone.net>; <jcarnevale@gnilink.net>; <elouie@yahoo.com>
Cc: <ccielab@groupstudy.com>
Sent: Friday, November 16, 2001 3:28 AM
Subject: Re: A very basic question : BGP
> I agree with Jason.
>
> If no IGP is used the source address of the ping would be on the outgoing
> interface of AS4 192.168.1.10 (network 192.168.1.8/30). If you look at the
> route table in AS1 the route for network 192.168.1.8/30 will not be in
> there, as AS4 has not injected this route into BGP with the network
command
> and will not appear in the bgp and route table of AS1. To prove it run
debug
> ip packet in AS1 whilst pinging from AS4 and it will output (no route to
> destination).
>
> You can do 2 things...
>
> 1) inject into BGP network 192.168.1.8/30 in AS4
>
> 2) inject a loopback address into BGP and use the extended ping function
to
> change source address to the loopback address.
>
>
> Percy
>
>
>
> >From: "Thekkethala" <thek@mediaone.net>
> >Reply-To: "Thekkethala" <thek@mediaone.net>
> >To: "Carnevale, Jason" <jcarnevale@gnilink.net>, "EA Louie"
> ><elouie@yahoo.com>
> >CC: "Carnevale, Jason" <jcarnevale@gnilink.net>, <ccielab@groupstudy.com>
> >Subject: Re: A very basic question : BGP
> >Date: Fri, 16 Nov 2001 03:47:09 -0500
> >
> >thanks Jason for that note - to just continue this thread
> >
> >If we run an IGP between the AS's - then I am wondering now ...what the
use
> >of BGP between these AS's ?? I think its 3:40 am in the morning and my
> >mind's going fuzzy.
> >
> >I mean in that sense, its like having an IGP setup in a way isnt it - say
> >like OSPF with all AS's under an area 0 type-of-thing.
> >
> >To my understanding BGP really is the carrier of " WHAT routes are
> >available
> >in this AS" and that info goes across the EBGP/IBGP links and ...
> >Inside each AS you need an IGP to ACTUALLY ROUTE around to reach those
> >networks inside the AS.
> >
> >So now IGP's used between AS's ???
> >
> >I am still stuck in a way, on the "EBGP links" between the AS's - it cant
> >be
> >right to run an IGP process on an EBGP Interface ( I know yu can but in a
> >real world scenario it does not sound right ..or does it ??)
> >
> >Dont get me wrong but I too have the same thoughts as yu and was
perplexed
> >about BGP's role suddenly
> >
> >----- Original Message -----
> >From: "Carnevale, Jason" <jcarnevale@gnilink.net>
> >To: "'Thekkethala'" <thek@mediaone.net>; "EA Louie" <elouie@yahoo.com>
> >Cc: "Carnevale, Jason" <jcarnevale@gnilink.net>; <ccielab@groupstudy.com>
> >Sent: Friday, November 16, 2001 3:04 AM
> >Subject: RE: A very basic question : BGP
> >
> >
> > > ok, I see what is happening. The answer to your question is no you do
> >not
> > > need to add the network statement or redistribute statement at each
> >router.
> > > The problem is a return path issue. All the routers no how to reach
the
> > > loopback because of bgp and it will make it there because everything
is
> > > directly connected. This means the route is in the table. The problem
> > > is...the router in AS 1 does not know how to reach the ip address on
the
> > > router in AS4. This is not in the table. You need to either add a
> >loopback
> > > at as4 and add that to bgp, when pinging the interface on as 1 source
> >the
> > > loopback on as 4 and it will work. If you want all routers to work
then
> >you
> > > need to run ospf, eigrp etc.... on all the routers and put all the
> > > interfaces in the igp protocol and you will be set. Here is a sample
> >config
> > > for each device.
> > >
> > >
> > > hope this helps
> > >
> > > -Jason
> > >
> > >
> > > router 1:
> > >
> > > sh run
> > > Building configuration...
> > >
> > > Current configuration:
> > > !
> > > version 12.0
> > > service timestamps debug uptime
> > > service timestamps log uptime
> > > no service password-encryption
> > > !
> > > hostname r1
> > > !
> > > no logging console
> > > !
> > > ip subnet-zero
> > > no ip domain-lookup
> > > !
> > > !
> > > !
> > > interface Loopback0
> > > description SIMULATED LAN INTERFACE
> > > ip address 11.1.1.1 255.255.255.0
> > > no ip directed-broadcast
> > > !
> > > interface Ethernet0
> > > no ip address
> > > no ip directed-broadcast
> > > shutdown
> > > !
> > > interface Serial0
> > > description CONNECTION TO FRAME-RELAY NETWORK
> > > no ip address
> > > no ip directed-broadcast
> > > encapsulation frame-relay IETF
> > > no ip mroute-cache
> > > frame-relay lmi-type ansi
> > > !
> > > interface Serial0.1 point-to-point
> > > description CONNECTION TO R2
> > > ip address 192.168.1.1 255.255.255.252
> > > no ip directed-broadcast
> > > frame-relay interface-dlci 102
> > > !
> > > interface Serial1
> > > no ip address
> > > no ip directed-broadcast
> > > shutdown
> > > !
> > > router ospf 110
> > > network 192.168.1.1 0.0.0.0 area 0
> > > !
> > > router bgp 1
> > > network 11.1.1.0 mask 255.255.255.0
> > > neighbor 192.168.1.2 remote-as 2
> > > neighbor 192.168.1.2 description BGP SESSION TO R2
> > > no auto-summary
> > > !
> > > ip classless
> > > !
> > > !
> > > !
> > > line con 0
> > > exec-timeout 0 0
> > > transport input none
> > > escape-character 3
> > > line aux 0
> > > line vty 0 4
> > > login
> > > !
> > > end
> > >
> > > r1#term len 0
> > > r1#sh ip ro
> > > Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B -
BGP
> > > D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> > > N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
> > > E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
> > > i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * -
candidate
> > > default
> > > U - per-user static route, o - ODR
> > > T - traffic engineered route
> > >
> > > Gateway of last resort is not set
> > >
> > > 11.0.0.0/24 is subnetted, 1 subnets
> > > C 11.1.1.0 is directly connected, Loopback0
> > > 192.168.1.0/30 is subnetted, 3 subnets
> > > O 192.168.1.8 [110/192] via 192.168.1.2, 00:00:57, Serial0.1
> > > C 192.168.1.0 is directly connected, Serial0.1
> > > O 192.168.1.4 [110/128] via 192.168.1.2, 00:00:57, Serial0.1
> > > r1#sh ip bgp
> > > BGP table version is 2, local router ID is 192.168.1.1
> > > Status codes: s suppressed, d damped, h history, * valid, > best, i -
> > > internal
> > > Origin codes: i - IGP, e - EGP, ? - incomplete
> > >
> > > Network Next Hop Metric LocPrf Weight Path
> > > *> 11.1.1.0/24 0.0.0.0 0 32768 i
> > > r1#
> > >
> > > router 2
> > >
> > > sh run
> > > Building configuration...
> > >
> > > Current configuration:
> > > !
> > > version 12.0
> > > service timestamps debug uptime
> > > service timestamps log uptime
> > > no service password-encryption
> > > !
> > > hostname R2
> > > !
> > > logging buffered 10000 debugging
> > > no logging console
> > > !
> > > ip subnet-zero
> > > no ip domain-lookup
> > > !
> > > !
> > > !
> > > interface Serial0
> > > description CONNECTION TO FRAME-RELAY NETWORK
> > > no ip address
> > > no ip directed-broadcast
> > > encapsulation frame-relay IETF
> > > no ip mroute-cache
> > > no fair-queue
> > > frame-relay lmi-type ansi
> > > !
> > > interface Serial0.1 point-to-point
> > > description CONNECTION TO R1
> > > ip address 192.168.1.2 255.255.255.252
> > > no ip directed-broadcast
> > > frame-relay interface-dlci 201
> > > !
> > > interface Serial0.2 point-to-point
> > > description CONNECTION TO R3
> > > ip address 192.168.1.5 255.255.255.252
> > > no ip directed-broadcast
> > > frame-relay interface-dlci 203
> > > !
> > > interface Serial1
> > > no ip address
> > > no ip directed-broadcast
> > > shutdown
> > > !
> > > interface TokenRing0
> > > no ip address
> > > no ip directed-broadcast
> > > shutdown
> > > !
> > > router ospf 110
> > > network 192.168.1.2 0.0.0.0 area 0
> > > network 192.168.1.5 0.0.0.0 area 0
> > > !
> > > router bgp 2
> > > neighbor 192.168.1.1 remote-as 1
> > > neighbor 192.168.1.1 description BGP SESSION TO R1
> > > neighbor 192.168.1.6 remote-as 3
> > > neighbor 192.168.1.6 description BGP SESSION TO R3
> > > !
> > > ip classless
> > > !
> > > !
> > > !
> > > line con 0
> > > exec-timeout 0 0
> > > transport input none
> > > line aux 0
> > > line vty 0 4
> > > !
> > > end
> > >
> > > R2# sh ip ro
> > > Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B -
BGP
> > > D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> > > N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
> > > E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
> > > i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * -
candidate
> > > default
> > > U - per-user static route, o - ODR
> > > T - traffic engineered route
> > >
> > > Gateway of last resort is not set
> > >
> > > 11.0.0.0/24 is subnetted, 1 subnets
> > > B 11.1.1.0 [20/0] via 192.168.1.1, 00:08:50
> > > 192.168.1.0/30 is subnetted, 3 subnets
> > > O 192.168.1.8 [110/128] via 192.168.1.6, 00:01:30, Serial0.2
> > > C 192.168.1.0 is directly connected, Serial0.1
> > > C 192.168.1.4 is directly connected, Serial0.2
> > > R2#sh ip bgp
> > > BGP table version is 2, local router ID is 192.168.1.5
> > > Status codes: s suppressed, d damped, h history, * valid, > best, i -
> > > internal
> > > Origin codes: i - IGP, e - EGP, ? - incomplete
> > >
> > > Network Next Hop Metric LocPrf Weight Path
> > > *> 11.1.1.0/24 192.168.1.1 0 0 1 i
> > > R2#
> > >
> > >
> > > router 3
> > >
> > > sh run
> > > Building configuration...
> > >
> > > Current configuration:
> > > !
> > > version 12.0
> > > service timestamps debug uptime
> > > service timestamps log uptime
> > > no service password-encryption
> > > !
> > > hostname R3
> > > !
> > > logging buffered 10000 debugging
> > > no logging console
> > > !
> > > ip subnet-zero
> > > no ip domain-lookup
> > > !
> > > !
> > > !
> > > interface Ethernet0
> > > no ip address
> > > no ip directed-broadcast
> > > shutdown
> > > !
> > > interface Serial0
> > > description CONNECTION TO FRAME-RELAY NETWORK
> > > no ip address
> > > no ip directed-broadcast
> > > encapsulation frame-relay IETF
> > > no ip mroute-cache
> > > no fair-queue
> > > frame-relay lmi-type ansi
> > > !
> > > interface Serial0.1 point-to-point
> > > description CONNECTION TO R2
> > > ip address 192.168.1.6 255.255.255.252
> > > no ip directed-broadcast
> > > frame-relay interface-dlci 302
> > > !
> > > interface Serial0.2 point-to-point
> > > description CONNECTION TO R4
> > > ip address 192.168.1.9 255.255.255.252
> > > no ip directed-broadcast
> > > frame-relay interface-dlci 304
> > > !
> > > interface Serial1
> > > no ip address
> > > no ip directed-broadcast
> > > shutdown
> > > !
> > > router ospf 110
> > > network 192.168.1.6 0.0.0.0 area 0
> > > network 192.168.1.9 0.0.0.0 area 0
> > > !
> > > router bgp 3
> > > neighbor 192.168.1.5 remote-as 2
> > > neighbor 192.168.1.5 description BGP SESSION TO R2
> > > neighbor 192.168.1.10 remote-as 4
> > > neighbor 192.168.1.10 description BGP SESSION TO R4
> > > !
> > > ip classless
> > > !
> > > !
> > > !
> > > line con 0
> > > exec-timeout 0 0
> > > transport input none
> > > line aux 0
> > > line vty 0 4
> > > !
> > > end
> > >
> > > R3# sh ip ro
> > > Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B -
BGP
> > > D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> > > N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
> > > E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
> > > i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * -
candidate
> > > default
> > > U - per-user static route, o - ODR
> > > T - traffic engineered route
> > >
> > > Gateway of last resort is not set
> > >
> > > 11.0.0.0/24 is subnetted, 1 subnets
> > > B 11.1.1.0 [20/0] via 192.168.1.5, 00:09:36
> > > 192.168.1.0/30 is subnetted, 3 subnets
> > > C 192.168.1.8 is directly connected, Serial0.2
> > > O 192.168.1.0 [110/128] via 192.168.1.5, 00:02:23, Serial0.1
> > > C 192.168.1.4 is directly connected, Serial0.1
> > > R3#sh ip bgp
> > > BGP table version is 3, local router ID is 192.168.1.9
> > > Status codes: s suppressed, d damped, h history, * valid, > best, i -
> > > internal
> > > Origin codes: i - IGP, e - EGP, ? - incomplete
> > >
> > > Network Next Hop Metric LocPrf Weight Path
> > > *> 11.1.1.0/24 192.168.1.5 0 2 1 i
> > > R3#
> > >
> > > router 4
> > >
> > > sh run
> > > Building configuration...
> > >
> > > Current configuration:
> > > !
> > > version 12.0
> > > service timestamps debug uptime
> > > service timestamps log uptime
> > > no service password-encryption
> > > !
> > > hostname R4
> > > !
> > > logging buffered 10000 debugging
> > > no logging console
> > > !
> > > ip subnet-zero
> > > no ip domain-lookup
> > > isdn switch-type basic-5ess
> > > !
> > > !
> > > !
> > > interface Serial0
> > > description CONNECTION TO FRAME-RELAY NETWORK
> > > no ip address
> > > no ip directed-broadcast
> > > encapsulation frame-relay IETF
> > > ip ospf network point-to-multipoint
> > > no ip mroute-cache
> > > no fair-queue
> > > frame-relay lmi-type ansi
> > > !
> > > interface Serial0.1 point-to-point
> > > description CONNECTION TO R3
> > > ip address 192.168.1.10 255.255.255.252
> > > no ip directed-broadcast
> > > frame-relay interface-dlci 403
> > > !
> > > interface Serial1
> > > no ip address
> > > no ip directed-broadcast
> > > shutdown
> > > !
> > > interface TokenRing0
> > > description CONNECTION TO R6 TO0
> > > no ip address
> > > no ip directed-broadcast
> > > ip ospf authentication-key cisco
> > > ip ospf cost 1
> > > ip ospf priority 100
> > > shutdown
> > > ring-speed 16
> > > !
> > > interface BRI0
> > > no ip address
> > > no ip directed-broadcast
> > > shutdown
> > > isdn switch-type basic-5ess
> > > !
> > > router ospf 110
> > > network 192.168.1.10 0.0.0.0 area 0
> > > !
> > > router bgp 4
> > > neighbor 192.168.1.9 remote-as 3
> > > neighbor 192.168.1.9 description BGP SESSION TO R3
> > > !
> > > ip classless
> > > !
> > > !
> > > !
> > > line con 0
> > > exec-timeout 0 0
> > > transport input none
> > > escape-character 3
> > > line aux 0
> > > line vty 0 4
> > > login
> > > !
> > > end
> > >
> > > R4# sh ip ro
> > > Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B -
BGP
> > > D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> > > N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
> > > E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
> > > i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * -
candidate
> > > default
> > > U - per-user static route, o - ODR
> > > T - traffic engineered route
> > >
> > > Gateway of last resort is not set
> > >
> > > 11.0.0.0/24 is subnetted, 1 subnets
> > > B 11.1.1.0 [20/0] via 192.168.1.9, 00:10:01
> > > 192.168.1.0/30 is subnetted, 3 subnets
> > > C 192.168.1.8 is directly connected, Serial0.1
> > > O 192.168.1.0 [110/192] via 192.168.1.9, 00:02:41, Serial0.1
> > > O 192.168.1.4 [110/128] via 192.168.1.9, 00:02:41, Serial0.1
> > > R4#sh ip bgp
> > > BGP table version is 2, local router ID is 192.168.1.10
> > > Status codes: s suppressed, d damped, h history, * valid, > best, i -
> > > internal
> > > Origin codes: i - IGP, e - EGP, ? - incomplete
> > >
> > > Network Next Hop Metric LocPrf Weight Path
> > > *> 11.1.1.0/24 192.168.1.9 0 3 2 1 i
> > > R4#ping 11.1.1.1
> > >
> > > Type escape sequence to abort.
> > > Sending 5, 100-byte ICMP Echos to 11.1.1.1, timeout is 2 seconds:
> > > !!!!!
> > > Success rate is 100 percent (5/5), round-trip min/avg/max =
172/172/176
> >ms
> > > R4#
> > >
> > > frame-switch
> > >
> > > term len 0
> > > FRAME-SW#sh run
> > > Building configuration...
> > >
> > > Current configuration:
> > > !
> > > version 12.0
> > > service timestamps debug uptime
> > > service timestamps log uptime
> > > no service password-encryption
> > > !
> > > hostname FRAME-SW
> > > !
> > > logging buffered 10000 debugging
> > > no logging console
> > > !
> > > ip subnet-zero
> > > no ip domain-lookup
> > > frame-relay switching
> > > !
> > > !
> > > !
> > > !
> > > !
> > > interface Ethernet0/0
> > > no ip address
> > > no ip directed-broadcast
> > > shutdown
> > > !
> > > interface Serial1/0
> > > no ip address
> > > no ip directed-broadcast
> > > no ip mroute-cache
> > > shutdown
> > > no fair-queue
> > > !
> > > interface Serial1/1
> > > description CONNECTION TO R1 S0
> > > no ip address
> > > no ip directed-broadcast
> > > encapsulation frame-relay IETF
> > > clockrate 64000
> > > frame-relay lmi-type ansi
> > > frame-relay intf-type dce
> > > frame-relay route 102 interface Serial1/2 201
> > > !
> > > interface Serial1/2
> > > description CONNECTION TO R2 S0
> > > no ip address
> > > no ip directed-broadcast
> > > encapsulation frame-relay IETF
> > > clockrate 64000
> > > frame-relay lmi-type ansi
> > > frame-relay intf-type dce
> > > frame-relay route 201 interface Serial1/1 102
> > > frame-relay route 203 interface Serial1/3 302
> > > !
> > > interface Serial1/3
> > > description CONNECTION TO R3 S0
> > > no ip address
> > > no ip directed-broadcast
> > > encapsulation frame-relay IETF
> > > clockrate 64000
> > > frame-relay lmi-type ansi
> > > frame-relay intf-type dce
> > > frame-relay route 302 interface Serial1/2 203
> > > frame-relay route 304 interface Serial1/4 403
> > > !
> > > interface Serial1/4
> > > description CONNECTION TO R4 S0
> > > no ip address
> > > no ip directed-broadcast
> > > encapsulation frame-relay IETF
> > > clockrate 64000
> > > frame-relay lmi-type ansi
> > > frame-relay intf-type dce
> > > frame-relay route 403 interface Serial1/3 304
> > > !
> > > interface Serial1/5
> > > no ip address
> > > no ip directed-broadcast
> > > shutdown
> > > !
> > > interface Serial1/6
> > > no ip address
> > > no ip directed-broadcast
> > > shutdown
> > > !
> > > interface Serial1/7
> > > no ip address
> > > no ip directed-broadcast
> > > shutdown
> > > !
> > > ip classless
> > > !
> > > !
> > > line con 0
> > > exec-timeout 0 0
> > > transport input none
> > > line aux 0
> > > line vty 0 4
> > > !
> > > end
> > >
> > > FRAME-SW#
> > >
> > > -----Original Message-----
> > > From: Thekkethala [mailto:thek@mediaone.net]
> > > Sent: Friday, November 16, 2001 2:39 AM
> > > To: EA Louie
> > > Cc: jcarnevale@gnilink.net; ccielab@groupstudy.com
> > > Subject: Re: A very basic question : BGP
> > >
> > >
> > > apologise for not being clear ....
> > >
> > > The query really is : Do I need to redistribute by directly connected
> >(Ebgp)
> > > links that are setup between AS's,into bgp at each of the routers in
the
> > > example ?
> > >
> > > I just found out that when i did a redistribute connected (under bgp)
on
> >all
> > > of the routers - the ping goes through from AS4 to the loopback
address
> >on
> > > AS1 ?? My BGP table grew too as a result of all the entries ...
> > >
> > > Therefore : sounds like EBGP links need to be explicitly brought into
> >the
> > > "bgp table" across all routers for an end to end IP connectivity to
> >happen
> > > (network/redistribute connected...)
> > >
> > > sounds a bit off .... or i am missing something elementary !!!
> > >
> > > ----- Original Message -----
> > > From: "EA Louie" <elouie@yahoo.com>
> > > To: "Thekkethala" <thek@mediaone.net>; <ccielab@groupstudy.com>
> > > Sent: Friday, November 16, 2001 2:18 AM
> > > Subject: Re: A very basic question : BGP
> > >
> > >
> > > > Try doing a traceroute to see where your ping is failing. Post
those
> > > > results. Also, try your ping/traceroute from AS1 to AS4 and post
> >those
> > > > results.
> > > >
> > > > -e-
> > > >
> > > > ----- Original Message -----
> > > > From: "Thekkethala" <thek@mediaone.net>
> > > > To: <ccielab@groupstudy.com>
> > > > Sent: Thursday, November 15, 2001 10:49 PM
> > > > Subject: A very basic question : BGP
> > > >
> > > >
> > > > > Just a sudden 'shake-up' in my fundamentals all of a sudden
> > > > >
> > > > > Here is the clarification. (EBGP links - do they need to be leaked
> >???)
> > > > >
> > > > > 1. You have multiple AS's and have EBGP running between them all.
> > > > >
> > > > > as1 ------->as2----->as3------->as4 (a single router in each AS
for
> > > > example)
> > > > >
> > > > > lets say yu configure a loopback address in as1 and leak it into
> >bgp
> > > via
> > > > a
> > > > > network statement in as1.
> > > > >
> > > > > Now, keeping the config (basic) as is, yu sit on the router on as4
> >and
> > > try
> > > > a
> > > > > ping back to as1 to this interface. It does no go thru. However
all
> >the
> > > > BGP
> > > > > tables enroute indicate this entry and since they are directly
> > > connected
> > > > ebgp
> > > > > setups, the next hop are there in the ip routing table as well
> >(directly
> > > > > connected).I then did a redistribute-connected under the bgp
process
> >on
> > > > ALL
> > > > > the routers and tried again - no luck in reaching the loopback
> >address
> > > in
> > > > as1
> > > > > FROM as4 - however from as2 no problems / as3 and as4 no go at all
> >!!
> > > > >
> > > > > My Question>
> > > > > 1. The eBGP links between routers :
> > > > >
> > > > > Do we ALWAYS need to consciously redistribute them in BGP setup
> > > > > (using either the redistribute-connected or network statement
along
> >with
> > > a
> > > > no
> > > > > auto-summary) to enable a ping / traceroute etc .. for ip
basically
> > > > > ...........
> > > > >
> > > > > I am sorry if this sounds really elementary ... but am quite
puzzled
> >-
> > > > what if
> > > > > I have a setup involving 50/60 ebgp session (in theory I mean)
> >....!!!!!
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