Remove-Private-As

Test BGP address-family ipv6-unicast remove-private-as functionality. When a router receives routes from a neighbor using a private AS number (64512-65534), those private AS numbers appear in the AS-path. The remove-private-as command strips these private AS numbers from the AS-path before advertising routes to an eBGP peer.

../../../../../../_images/remove-private-as.svg

Test eBGP IPv6 - Without remove-private-as shows private AS in path

Description

Baseline test showing default behavior where private AS numbers are visible in the AS-path. DUT1 uses private AS 65001 and originates route 2001:db8:100::/64. DUT0 (AS 100) receives the route and forwards it to DUT2 (AS 200).

Scenario

Step 1: Set the following configuration in DUT0 :

set interfaces ethernet eth0 address '2001:db8:1::100/64'
set interfaces ethernet eth1 address '2001:db8:2::100/64'
set protocols bgp 100 neighbor dut1 address-family ipv6-unicast activate
set protocols bgp 100 neighbor dut1 address-family ipv6-unicast route-map import PERMIT
set protocols bgp 100 neighbor dut1 remote-address '2001:db8:1::200'
set protocols bgp 100 neighbor dut1 remote-as 65001
set protocols bgp 100 neighbor dut2 address-family ipv6-unicast activate
set protocols bgp 100 neighbor dut2 address-family ipv6-unicast route-map export PERMIT
set protocols bgp 100 neighbor dut2 remote-address '2001:db8:2::200'
set protocols bgp 100 neighbor dut2 remote-as 200
set protocols bgp 100 parameters router-id 1.1.1.100
set protocols route-map PERMIT rule 1 action permit
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 2: Set the following configuration in DUT1 :

set interfaces dummy dum0 address '2001:db8:100::1/64'
set interfaces ethernet eth0 address '2001:db8:1::200/64'
set protocols bgp 65001 address-family ipv6-unicast redistribute connected
set protocols bgp 65001 neighbor peer address-family ipv6-unicast activate
set protocols bgp 65001 neighbor peer address-family ipv6-unicast route-map export PERMIT
set protocols bgp 65001 neighbor peer remote-address '2001:db8:1::100'
set protocols bgp 65001 neighbor peer remote-as 100
set protocols bgp 65001 parameters router-id 1.1.1.200
set protocols route-map PERMIT rule 1 action permit
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 3: Set the following configuration in DUT2 :

set interfaces ethernet eth1 address '2001:db8:2::200/64'
set protocols bgp 200 neighbor peer address-family ipv6-unicast activate
set protocols bgp 200 neighbor peer address-family ipv6-unicast route-map import PERMIT
set protocols bgp 200 neighbor peer remote-address '2001:db8:2::100'
set protocols bgp 200 neighbor peer remote-as 100
set protocols bgp 200 parameters router-id 1.1.1.201
set protocols route-map PERMIT rule 1 action permit
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Attention

Verify eBGP sessions establish on DUT0.

Step 4: Run command protocols bgp show ipv6 summary at DUT0 and check if output matches the following regular expressions:

2001:db8:1::200.*Established.*\n.*2001:db8:2::200.*Established
Show output
IPv6 Unicast Summary:
BGP router identifier 1.1.1.100, local AS number 100 VRF default vrf-id 0
BGP table version 2
RIB entries 3, using 384 bytes of memory
Peers 2, using 47 KiB of memory

Neighbor        LocalAddr       V         AS   MsgRcvd   MsgSent   TblVer  InQ OutQ  Up/Down        State   PfxRcd   PfxSnt Desc
2001:db8:1::200 0.0.0.0         4      65001         7         7        2    0    0 00:00:03  Established        2 (Policy) N/A
2001:db8:2::200 0.0.0.0         4        200         2         3        0    0    0 00:00:01  Established (Policy)        0 N/A

Total number of neighbors 2

Attention

Verify DUT0 receives route 2001:db8:100::/64 from DUT1.

Step 5: Run command protocols bgp show ipv6 at DUT0 and check if output matches the following regular expressions:

2001:db8:100::/64
Show output
BGP table version is 2, local router ID is 1.1.1.100, vrf id 0
Default local pref 100, local AS 100
local address -
Status codes:  s suppressed, d damped, h history, u unsorted, * valid, > best, = multipath,
               i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes:  i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *>  2001:db8:1::/64  fe80::dcad:beff:feef:6c10
                                             0             0 65001 ?
 *>  2001:db8:100::/64
                    fe80::dcad:beff:feef:6c10
                                             0             0 65001 ?

Displayed 2 routes and 2 total paths

Attention

Verify DUT2 receives route 2001:db8:100::/64 with private AS 65001 in path.

Step 6: Run command protocols bgp show ipv6 2001:db8:100::/64 at DUT2 and check if output matches the following regular expressions:

100 65001
Show output
BGP routing table entry for 2001:db8:100::/64, version 2
Paths: (1 available, best #1, table default)
  Not advertised to any peer
  100 65001
    2001:db8:2::100 from 2001:db8:2::100 (1.1.1.100)
    (fe80::dcad:beff:feef:6c01) (used)
      Origin incomplete, valid, external, best (First path received)
      Last update: Thu Mar  5 14:45:17 2026

Test eBGP IPv6 - Remove-private-as strips private AS from path

Description

Test BGP remove-private-as which strips private AS numbers from the AS-path before advertising to eBGP peers. DUT1 uses private AS 65001 and originates route 2001:db8:100::/64. DUT0 (AS 100) has remove-private-as configured toward DUT2.

Scenario

Step 1: Set the following configuration in DUT0 :

set interfaces ethernet eth0 address '2001:db8:1::100/64'
set interfaces ethernet eth1 address '2001:db8:2::100/64'
set protocols bgp 100 neighbor dut1 address-family ipv6-unicast activate
set protocols bgp 100 neighbor dut1 address-family ipv6-unicast route-map import PERMIT
set protocols bgp 100 neighbor dut1 remote-address '2001:db8:1::200'
set protocols bgp 100 neighbor dut1 remote-as 65001
set protocols bgp 100 neighbor dut2 address-family ipv6-unicast activate
set protocols bgp 100 neighbor dut2 address-family ipv6-unicast remove-private-as
set protocols bgp 100 neighbor dut2 address-family ipv6-unicast route-map export PERMIT
set protocols bgp 100 neighbor dut2 remote-address '2001:db8:2::200'
set protocols bgp 100 neighbor dut2 remote-as 200
set protocols bgp 100 parameters router-id 1.1.1.100
set protocols route-map PERMIT rule 1 action permit
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 2: Set the following configuration in DUT1 :

set interfaces dummy dum0 address '2001:db8:100::1/64'
set interfaces ethernet eth0 address '2001:db8:1::200/64'
set protocols bgp 65001 address-family ipv6-unicast redistribute connected
set protocols bgp 65001 neighbor peer address-family ipv6-unicast activate
set protocols bgp 65001 neighbor peer address-family ipv6-unicast route-map export PERMIT
set protocols bgp 65001 neighbor peer remote-address '2001:db8:1::100'
set protocols bgp 65001 neighbor peer remote-as 100
set protocols bgp 65001 parameters router-id 1.1.1.200
set protocols route-map PERMIT rule 1 action permit
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 3: Set the following configuration in DUT2 :

set interfaces ethernet eth1 address '2001:db8:2::200/64'
set protocols bgp 200 neighbor peer address-family ipv6-unicast activate
set protocols bgp 200 neighbor peer address-family ipv6-unicast route-map import PERMIT
set protocols bgp 200 neighbor peer remote-address '2001:db8:2::100'
set protocols bgp 200 neighbor peer remote-as 100
set protocols bgp 200 parameters router-id 1.1.1.201
set protocols route-map PERMIT rule 1 action permit
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Attention

Verify eBGP sessions establish on DUT0.

Step 4: Run command protocols bgp show ipv6 summary at DUT0 and check if output matches the following regular expressions:

2001:db8:1::200.*Established.*\n.*2001:db8:2::200.*Established
Show output
IPv6 Unicast Summary:
BGP router identifier 1.1.1.100, local AS number 100 VRF default vrf-id 0
BGP table version 2
RIB entries 3, using 384 bytes of memory
Peers 2, using 47 KiB of memory

Neighbor        LocalAddr       V         AS   MsgRcvd   MsgSent   TblVer  InQ OutQ  Up/Down        State   PfxRcd   PfxSnt Desc
2001:db8:1::200 0.0.0.0         4      65001         8         6        2    0    0 00:00:04  Established        2 (Policy) N/A
2001:db8:2::200 0.0.0.0         4        200         4         5        2    0    0 00:00:01  Established (Policy)        2 N/A

Total number of neighbors 2

Attention

Verify DUT0 receives route 2001:db8:100::/64 from DUT1 with private AS in path.

Step 5: Run command protocols bgp show ipv6 2001:db8:100::/64 at DUT0 and check if output matches the following regular expressions:

65001
Show output
BGP routing table entry for 2001:db8:100::/64, version 2
Paths: (1 available, best #1, table default)
  Advertised to peers:
  2001:db8:2::200
  65001
    2001:db8:1::200 from 2001:db8:1::200 (1.1.1.200)
    (fe80::dcad:beff:feef:6c10) (used)
      Origin incomplete, metric 0, valid, external, best (First path received)
      Last update: Thu Mar  5 14:45:34 2026

Attention

Verify DUT2 sees only AS 100 in the path (private AS was removed by DUT0).

Step 6: Run command protocols bgp show ipv6 2001:db8:100::/64 at DUT2 and check if output matches the following regular expressions:

(?m)^\s+100\s*$
Show output
BGP routing table entry for 2001:db8:100::/64, version 2
Paths: (1 available, best #1, table default)
  Not advertised to any peer
  100
    2001:db8:2::100 from 2001:db8:2::100 (1.1.1.100)
    (fe80::dcad:beff:feef:6c01) (used)
      Origin incomplete, valid, external, best (First path received)
      Last update: Thu Mar  5 14:45:37 2026