On 2011-10-18, Laurent CARON <lca...@unix-scripts.info> wrote:
> Hi,
>
> I'm currently implementing a multi ISP BGP solution:
>
> 2 BGP routers on a site, each hooked to a different ISP.
>
>
> Problem: The rib of rtr-1/rtr-2 are having the following entries:
>
> flags destination gateway lpref med aspath origin
> *> 1.0.4.0/22 EXTERNALGW_PROVIDER1 100 0 STRIPPED_ASPATH
> i
> I 1.0.4.0/22 EXTERNALGW_PROVIDER2 100 300 STRIPPED_ASPATH
> i
>
> Sure thing, EXTERNALGW_PROVIDER1 can not be reached from rtr-2 and
> EXTERNALGW_PROVIDER2 can not reached from rtr-1
EXTERNALGW_PROVIDER1 *should* be reachable from rtr-2 and vice-versa.
You should either have non-bgp routes to the gateway addresses (typically
ospf or static routes), or rewrite the addresses with 'nexthop self' for
your ibgp peers.
> Do you guys see any misconfiguration on my side ?
>From what you describe, yes there's misconfiguration, but between the
incomplete information pasted, and the mixing and matching of obfuscated
addresses above and non-obfuscated below, it's hard to help.
This is standard routing config, not openbgpd specific, so you should
probably read some guides to setting up BGP.
Might be able to help with some more information but really if you're
running BGP you need to know how to do this yourself otherwise you
will become really unstuck when things fail.
> Config of rtr-1:
>
> ifconfig lo1: 46.21.1.3
>
> ifconfig em3: 172.16.255.3
>
> $ route -n get 46.21.1.4
> route to: 46.21.1.4
> destination: 46.21.1.4
> gateway: 172.16.255.4
> interface: em3
> if address: 172.16.255.3
> priority: 8 (static)
> flags: <UP,GATEWAY,HOST,DONE,STATIC>
> use mtu expire
> 12676 0 0
>
> $ cat /etc/bgpd.conf
> AS 49463
> router-id 46.21.1.3
> holdtime 90
> holdtime min 3
> fib-update yes
>
> network 46.21.1.0/24
>
> group "iBGP peers" {
> remote-as 49463
> announce all
>
> neighbor 46.21.1.4 {
> descr iv4_gw-003_to_004
> local-address 46.21.1.3
> announce IPv4 unicast
> }
>
> group "eBGP transit" {
>
> remote-as 8218
> holdtime 30
> announce self
>
> neighbor 46.255.1.1 {
> descr ev4_gw-003_to_tr
> local-address 46.255.1.2
> announce IPv4 unicast
> announce IPv6 none
> }
> }
>
> Config of rtr-2:
>
> ifconfig lo1: 46.21.1.4
>
> ifconfig em3: 172.16.255.4
>
> $ route -n get 46.21.1.3
> route to: 46.21.1.3
> destination: 46.21.1.3
> gateway: 172.16.255.3
> interface: em3
> if address: 172.16.255.4
> priority: 8 (static)
> flags: <UP,GATEWAY,HOST,DONE,STATIC>
> use mtu expire
> 12676 0 0
>
>
> $ cat /etc/bgpd.conf
> AS 49463
> router-id 46.21.1.4
> holdtime 90
> holdtime min 3
> fib-update yes
>
> network 46.21.1.0/24
>
> group "iBGP peers" {
> remote-as 49463
> announce all
>
> neighbor 46.21.1.3 {
> descr iv4_gw-004_to_003
> local-address 46.21.1.4
> announce IPv4 unicast
> }
>
> group "eBGP transit" {
>
> remote-as 13193
> holdtime 30
> announce self
>
> neighbor 88.255.1.1 {
> descr ev3_gw-003_to_tr
> local-address 88.255.1.2
> announce IPv4 unicast
> announce IPv6 none
> }
> }
