Help with IBGP not advertisement routes - "rejected by protocol"

[Jeronimo de A. Barros]

Hi,

I have two routers running bird connected to two peers where one peer is my
own ISP and AS which lets us use his AS and was kind enough to allocate two
/24 for our networks so that we can have two sites in different locations
using BGP with a second ISP to be a multi-home system using only two /24.

This is our network (I hope you can understand my sketch):

Internet <-> BR1-AS1 <-> R1-AS1 <-> R2-AS1 <-> BR-AS2 <-> Internet
          |           |  ^               ^
          +> BR2-AS1 <+  +-> Net1/24     +-> Net2/24

So, our main ISP has IBGP sessions from its border-routers (BRx-AS1) to our
main router (R1-AS1) which in turn has another IBGP session with our second
router located at a remote site (R2-AS1). R2-AS1 has an BGP session with
the second ISP border router (BR-AS2).

Well, when all sessions are UP, Net1 and Net2 can reach the Internet and
each other without problems.

But, for example, if the BGP session between R2-AS1 and BR-AS2 goes down,
traffic between Net1 and Net2 continues OK, but Net2 can't reach the
Internet anymore. Or, in other words, the routes received from BRx-AS1 at
R1-AS1 are not being advertised to R2-AS1, in fact a "show protocol all" on
R1-AS1 shows its advertising only the direct connected networks and the
static routes to R2-AS1 and vice-versa:

BIRD 1.4.5 ready.
name     proto    table    state  since       info
R2-AS1   BGP      master   up     17:39:21    Established
  Router ID:      x.y.w.249
  Preference:     100
  Input filter:   ACCEPT
  Output filter:  ACCEPT
  Routes:         5 imported, 10 exported, 2 preferred
  Route change stats:     received   rejected   filtered    ignored
accepted
    Import updates:              5          0          0          0
 5
    Import withdraws:            0          0        ---          0
 0
    Export updates:         527178     527168          0        ---
10
    Export withdraws:           20        ---        ---        ---
 0
  BGP state:          Established
    Neighbor address: x.y.w.251
    Neighbor AS:      xxxx
    Neighbor ID:      x.y.w.251
    Neighbor caps:    refresh restart-aware AS4
    Session:          internal AS4
    Source address:   x.y.w.249
    Hold timer:       188/240
    Keepalive timer:  66/80

The debug shows a lot of "rejected by protocol" messages, which I can't
find a clear description of what is its meaning:

2015-02-18 16:55:48 <TRACE> kernel1 < replaced 148.208.146.0/24 via
x.y.z.29 on bond1
2015-02-18 16:55:48 <TRACE> BR1-AS1 < rejected by protocol 148.208.146.0/24
via x.y.z.29 on bond1
2015-02-18 16:55:48 <TRACE> BR2-AS1 < rejected by protocol 148.208.146.0/24
via x.y.z.29 on bond1
2015-02-18 16:55:48 <TRACE> R2-AS1 < rejected by protocol 148.208.146.0/24
via x.y.z.29 on bond1
2015-02-18 16:55:49 <TRACE> BR2-AS1 > added [best] 177.10.158.0/24 via
x.y.z.29 on bond1
2015-02-18 16:55:49 <TRACE> kernel1 < replaced 177.10.158.0/24 via x.y.z.29
on bond1
2015-02-18 16:55:49 <TRACE> BR1-AS1 < rejected by protocol 177.10.158.0/24
via x.y.z.29 on bond1
2015-02-18 16:55:49 <TRACE> BR2-AS1 < rejected by protocol 177.10.158.0/24
via x.y.z.29 on bond1
2015-02-18 16:55:49 <TRACE> R2-AS1 < rejected by protocol 177.10.158.0/24
via x.y.z.29 on bond1
2015-02-18 16:55:49 <TRACE> BR1-AS1 > removed 177.10.158.0/24 via x.y.z.27
on bond1

This is the template for the IBGP session between R1-AS1 and R2-AS1 (as
simple as possible):

template bgp ibgp_sites {
  local as myas;
  import all;
  export all;
  direct;
}

I know that BGP has a lot of subtle behaviors, and I'd like to know if
there is any way to make this work or if it's a dead end approach.

Thanks in advance for any help.

Jero

ps: sorry for my broken English
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