Default Route advertisement eBGP failover

Thanks for your reply joegoldman. I attached my filters from Towers 1, 2, and 3.

Tower1:

0 ;;; eBGP Core-QFX Allow-In
chain=ebgp-core-qfx5100-accept prefix=0.0.0.0/0 prefix-length=0 invert-match=no action=accept set-bgp-prepend-path=“”
1 chain=ebgp-core-qfx5100-accept invert-match=no action=discard set-bgp-prepend-path=“”
2 ;;; eBGP Core-QFX Allow-Out
chain=ebgp-core-qfx5100-announce prefix=10.50.105.0/24 prefix-length=24-32 invert-match=no action=accept
set-bgp-prepend-path=“”
3 chain=ebgp-core-qfx5100-announce prefix=10.105.0.0/22 prefix-length=22-32 invert-match=no action=accept
set-bgp-prepend-path=“”
4 chain=ebgp-core-qfx5100-announce prefix=10.0.0.0/8 prefix-length=22-32 invert-match=no action=accept set-bgp-prepend-path=“”
5 chain=ebgp-core-qfx5100-announce prefix=172.20.0.0/16 prefix-length=24-32 invert-match=no action=accept
set-bgp-prepend-path=“”
6 chain=ebgp-core-qfx5100-announce prefix=172.25.0.0/16 prefix-length=24-32 invert-match=no action=accept
set-bgp-prepend-path=“”
7 chain=ebgp-core-qfx5100-announce invert-match=no action=discard set-bgp-prepend-path=“”

8 ;;; eBGP Cedar Allow-Out (Tower2)
chain=ebgp-cedar-announce prefix=10.0.0.0/8 prefix-length=22-32 invert-match=no action=accept set-bgp-prepend-path=“”
9 chain=ebgp-cedar-announce prefix=172.20.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
10 chain=ebgp-cedar-announce prefix=172.25.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
11 chain=ebgp-cedar-announce prefix=0.0.0.0/0 prefix-length=0 invert-match=no action=accept set-bgp-prepend-path=“”
12 chain=ebgp-cedar-announce invert-match=no action=discard set-bgp-prepend-path=“”
13 ;;; eBGP Cedar Allow-In (Tower2)
chain=ebgp-cedar-accept prefix=10.0.0.0/8 prefix-length=22-32 invert-match=no action=accept set-bgp-prepend-path=“”
14 chain=ebgp-cedar-accept prefix=172.20.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
15 chain=ebgp-cedar-accept prefix=172.25.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
16 chain=ebgp-cedar-accept prefix=0.0.0.0/0 prefix-length=0 invert-match=no action=accept set-bgp-prepend-path=“”
17 chain=ebgp-cedar-accept invert-match=no action=discard set-bgp-prepend-path=“”

Tower2:
0 ;;; eBGP Riverview Allow-Out (Tower1)
chain=ebgp-riverview-announce prefix=10.0.0.0/8 prefix-length=22-32 invert-match=no action=accept set-bgp-prepend-path=“”
1 chain=ebgp-riverview-announce prefix=172.20.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
2 chain=ebgp-riverview-announce prefix=172.25.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
3 chain=ebgp-riverview-announce prefix=0.0.0.0/0 prefix-length=0 invert-match=no action=accept set-bgp-prepend-path=“”
4 chain=ebgp-riverview-announce invert-match=no action=discard set-bgp-prepend-path=“”
5 ;;; eBGP Riverview Allow-In (Tower1)
chain=ebgp-riverview-accept prefix=10.0.0.0/8 prefix-length=22-32 invert-match=no action=accept set-bgp-prepend-path=“”
6 chain=ebgp-riverview-accept prefix=172.20.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
7 chain=ebgp-riverview-accept prefix=172.25.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
8 chain=ebgp-riverview-accept prefix=0.0.0.0/0 prefix-length=0 invert-match=no action=accept set-bgp-prepend-path=“”
9 chain=ebgp-riverview-accept invert-match=no action=discard set-bgp-weight=150 set-bgp-prepend-path=“”

10 ;;; eBGP Willson Allow-Out (Tower3)
chain=ebgp-willson-announce prefix=10.0.0.0/8 prefix-length=22-32 invert-match=no action=accept set-bgp-prepend-path=“”
11 chain=ebgp-willson-announce prefix=172.20.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
12 chain=ebgp-willson-announce prefix=172.25.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
13 chain=ebgp-willson-announce prefix=0.0.0.0/0 prefix-length=0 invert-match=no action=accept set-bgp-prepend-path=“”
14 chain=ebgp-willson-announce invert-match=no action=discard set-bgp-prepend-path=“”
15 ;;; eBGP Willson Allow-In (Tower3)
chain=ebgp-willson-accept prefix=10.0.0.0/8 prefix-length=22-32 invert-match=no action=accept set-bgp-prepend-path=“”
16 chain=ebgp-willson-accept prefix=172.20.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
17 chain=ebgp-willson-accept prefix=172.25.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
18 chain=ebgp-willson-accept prefix=0.0.0.0/0 prefix-length=0 invert-match=no action=accept set-bgp-prepend-path=“”
19 chain=ebgp-willson-accept invert-match=no action=discard set-bgp-prepend-path=“”

Tower3:
0 ;;; eBGP Addison Allow-Out (Tower4)
chain=ebgp-addison-announce prefix=10.0.0.0/8 prefix-length=22-32 invert-match=no action=accept set-bgp-prepend-path=“”
1 chain=ebgp-addison-announce prefix=172.20.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
2 chain=ebgp-addison-announce prefix=172.25.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
3 chain=ebgp-addison-announce prefix=0.0.0.0/0 prefix-length=0 invert-match=no action=accept set-bgp-weight=0
set-bgp-prepend-path=“”
4 chain=ebgp-addison-announce invert-match=no action=discard set-bgp-prepend-path=“”

5 ;;; eBGP Addison Allow-In (Tower4)
chain=ebgp-addison-accept prefix=10.0.0.0/8 prefix-length=22-32 invert-match=no action=accept set-bgp-prepend-path=“”
6 chain=ebgp-addison-accept prefix=172.20.0.0/16 prefix-length=30-32 invert-match=no action=accept set-bgp-prepend-path=“”
7 chain=ebgp-addison-accept prefix=172.25.0.0/16 prefix-length=30-32 invert-match=no action=accept set-bgp-prepend-path=“”
8 chain=ebgp-addison-accept prefix=0.0.0.0/0 prefix-length=0 invert-match=no action=accept set-bgp-prepend-path=“”
9 chain=ebgp-addison-accept invert-match=no action=discard set-bgp-prepend-path=“”

10 ;;; eBGP Cedar Announce (Tower2)
chain=ebgp-cedar-announce prefix=10.0.0.0/8 prefix-length=22-32 invert-match=no action=accept set-bgp-weight=0
set-bgp-prepend-path=“”
11 chain=ebgp-cedar-announce prefix=172.25.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-weight=0
set-bgp-prepend-path=“”
12 chain=ebgp-cedar-announce prefix=172.20.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-weight=0
set-bgp-prepend-path=“”
13 chain=ebgp-cedar-announce prefix=0.0.0.0/0 prefix-length=0 invert-match=no action=accept set-bgp-weight=100
set-bgp-prepend-path=“”
14 chain=ebgp-cedar-announce invert-match=no action=discard set-bgp-prepend-path=“”

15 ;;; eBGP Cedar Allow-In (Tower2)
chain=ebgp-cedar-accept prefix=10.0.0.0/8 prefix-length=22-32 invert-match=no action=accept set-bgp-prepend-path=“”
16 chain=ebgp-cedar-accept prefix=172.20.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
17 chain=ebgp-cedar-accept prefix=172.25.0.0/16 prefix-length=24-32 invert-match=no action=accept set-bgp-prepend-path=“”
18 chain=ebgp-cedar-accept prefix=0.0.0.0/0 prefix-length=0 invert-match=no action=accept set-bgp-prepend-path=“”
19 chain=ebgp-cedar-accept invert-match=no action=discard set-bgp-prepend-path=“”