Configure FTD BGP over IPSec VPN

Introduction

This document describes how to configure Border Gateway Protocol (BGP) neighborship over an IPsec site-to-site VPN tunnel between two Cisco FirePower Threat Defense (FTD).

Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

• BGP configurations on FTD
• IPsec site-to-site VPN tunnel configurations on FTD

Components Used

The information in this document is based on Cisco FTDv running 6.4.0.7 and 6.4.0.9.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Configure

 This section describes the configuration needed on the FTDs to bring up BGP neighborship through an IPSec Tunnel.

Network Diagram

Configure IPSec VPN

Step 1. Create a new Point-to-Point VPN Topology.

Navigate to Devices > VPN > Site-to-Site, and add a new FirePower Threat Defense Device VPN.

Step 2. Configure FTD1 as one of the endpoints.

• Object network FTD1-Outside-IP contains the outside interface IP address of the FTD1.
• Objects obj-10.1.1.0 and obj-10.1.2.0 contain subnet 10.1.1.0/24 and 10.1.2.0/24 respectively. VPN traffic is generated from these subnets. In the BGP configuration section here, BGP is configured to advertise these subnets to its neighbors.

Step 3. Configure FTD2 as the second endpoint.

• Object network FTD2-Outside-IP contains the outside interface IP address of the FTD2.
• Objects obj-172.16.1.0 and obj-172.16.2.0 contain subnet 172.16.1.0/24 and 172.16.2.0/24 respectively. VPN traffic is generated from these subnets. In the BGP configuration section here, BGP is configured to advertise these subnets to its neighbors.

Step 4. Configure the IKE parameters.

1. Configure the IKEv2 policy.
2. Configure the Authentication Method (PSK/Certificate).

Step 5. Configure the necessary IPSec Parameters.

1. Configure Crypto map type (Static or Dynamic)
2. Configure IKEv2 Mode (Tunnel or Transport)
3. Configure IPSec Proposals
4. Enable Perfect Forward Secrecy (Optional)
5. Enable Reverse Route Injection (Optional)

Step 6. Configure Advanced Settings as needed.

Configure BGP

This is the procedure to configure FTD1 and FTD2.

Under Device Management and select the device, then navigate to Routing > BGP.

1. Enable BGP and configure the Autonomous System (AS) Number, as shown in this image.

2. Navigate to BGP > IPv4 and enable BGP IPv4 on the FTD, as shown in this image.

3. Under the Neighbor Tab, add the other FTD as a neighbor and enable the neighbor, as shown in this image.

4. Under the Networks Tab, add the networks that you want to advertise through BGP.

5. All other BGP settings are optional and you may configure them as per your environment.

Final Configuration on both the Devices

FTD1

!--- FTD Version ---!

ftd1# show version
----------------------[ ftd1 ]----------------------
Model                     : Cisco Firepower Threat Defense for VMWare (75) Version 6.4.0.7 (Build 53)
UUID                      : cbd4966c-daf4-11ea-8637-c8977622bc2d
Rules update version      : 2018-10-10-001-vrt
VDB version               : 309
----------------------------------------------------
Cisco Adaptive Security Appliance Software Version 9.12(2)151 


!--- Configure the Inside and outside interface ---!

interface GigabitEthernet0/0
 nameif outside
 cts manual
  propagate sgt preserve-untag
  policy static sgt disabled trusted
 security-level 0
 ip address 192.0.2.1 255.255.255.0
!
interface GigabitEthernet0/1
 nameif inside
 cts manual
  propagate sgt preserve-untag
  policy static sgt disabled trusted
 security-level 0
 ip address 10.1.1.1 255.255.255.0 


!--- Configure VPN ---!
!--- Configure IPSec Policy ---!
crypto ipsec ikev2 ipsec-proposal CSM_IP_1
protocol esp encryption des
protocol esp integrity sha-1


!--- Configure Crypto Map ---!
crypto map CSM_outside_map 1 match address CSM_IPSEC_ACL_2
crypto map CSM_outside_map 1 set peer 209.165.201.1
crypto map CSM_outside_map 1 set ikev2 ipsec-proposal CSM_IP_1
crypto map CSM_outside_map 1 set reverse-route


!--- Apply the Crypto Map to the outside interface ---!

crypto map CSM_outside_map interface outside


!--- Configure IKEv2 policy ---!
crypto ikev2 policy 80
encryption des
integrity sha
group 5
prf sha
lifetime seconds 86400


!--- Enable IKEv2 on the outside interface ---!

crypto ikev2 enable outside


!--- Configure BGP Router Process ---!

router bgp 100
bgp log-neighbor-changes
bgp router-id 10.127.248.35
address-family ipv4 unicast
neighbor 209.165.201.1 remote-as 100
neighbor 209.165.201.1 transport path-mtu-discovery disable
neighbor 209.165.201.1 activate
network 10.1.1.0 mask 255.255.255.0
network 10.1.2.0 mask 255.255.255.0
no auto-summary
no synchronization
exit-address-family
!


!--- Configure the necessary routes ---!

route outside 0.0.0.0 0.0.0.0 192.0.2.100 1
route inside 10.1.2.0 255.255.255.0 10.1.1.100 1

FTD2

!--- FTD Version ---!

ftd2# show version
----------------------[ ftd2 ]----------------------
Model                     : Cisco Firepower Threat Defense for VMWare (75) Version 6.4.0.9 (Build 62)
UUID                      : 4ebe8e3a-dd8d-11ea-a599-a348a450d5ff
Rules update version      : 2018-10-10-001-vrt
VDB version               : 309
----------------------------------------------------
Cisco Adaptive Security Appliance Software Version 9.12(2)33 


!--- Configure the Inside and outside interface ---!

interface GigabitEthernet0/0
 nameif outside
 cts manual
  propagate sgt preserve-untag
  policy static sgt disabled trusted
 security-level 0
 ip address 209.165.201.1 255.255.255.0
!
interface GigabitEthernet0/1
 nameif inside
 cts manual
  propagate sgt preserve-untag
  policy static sgt disabled trusted
 security-level 0
 ip address 172.16.1.1 255.255.255.0 


 !--- Configure VPN ---!
 !--- Configure IPSec Policy ---!

crypto ipsec ikev2 ipsec-proposal CSM_IP_1
protocol esp encryption des
protocol esp integrity sha-1


!--- Configure Crypto Map ---!

crypto map CSM_outside_map 2 match address CSM_IPSEC_ACL_2
crypto map CSM_outside_map 2 set peer 192.0.2.1
crypto map CSM_outside_map 2 set ikev2 ipsec-proposal CSM_IP_1
crypto map CSM_outside_map 2 set reverse-route


!--- Apply the Crypto Map to the outside interface ---!

crypto map CSM_outside_map interface outside


!--- Configure IKEv2 policy ---!

crypto ikev2 policy 80
encryption des
integrity sha
group 5
prf sha
lifetime seconds 86400


!--- Enable IKEv2 on the outside interface ---!

crypto ikev2 enable outside


!--- Configure BGP Router Process ---!

router bgp 100
bgp log-neighbor-changes
bgp router-id 10.127.248.36
address-family ipv4 unicast
neighbor 192.0.2.1 remote-as 100
neighbor 192.0.2.1 transport path-mtu-discovery disable
neighbor 192.0.2.1 activate
network 172.16.1.0 mask 255.255.255.0
network 172.16.2.0 mask 255.255.255.0
no auto-summary
no synchronization
exit-address-family


!--- Configure the necessary routes ---!

route outside 0.0.0.0 0.0.0.0 209.165.201.100 1
route inside 172.16.2.0 255.255.255.0 172.16.1.100 1

Verify

FTD1

!--- Check the IKEv2 sa with remote peer ---!

ftd1# show crypto ikev2 sa

IKEv2 SAs:

Session-id:34, Status:UP-ACTIVE, IKE count:1, CHILD count:1

Tunnel-id Local Remote Status Role
315310279 192.0.2.1/500 209.165.201.1/500 READY INITIATOR
Encr: DES, Hash: SHA96, DH Grp:5, Auth sign: PSK, Auth verify: PSK
Life/Active Time: 86400/32514 sec
Child sa: local selector 192.0.2.1/0 - 192.0.2.1/65535
remote selector 209.165.201.1/0 - 209.165.201.1/65535
ESP spi in/out: 0xd8ba0545/0x4b6beb6c


!--- Check the IPSec sa with remote peer and check the number of encrypts and decrypts---!

ftd1# show crypto ipsec sa
interface: outside
Crypto map tag: CSM_outside_map, seq num: 1, local addr: 192.0.2.1

access-list CSM_IPSEC_ACL_2 extended permit ip host 192.0.2.1 host 209.165.201.1
local ident (addr/mask/prot/port): (192.0.2.1/255.255.255.255/0/0)
remote ident (addr/mask/prot/port): (209.165.201.1/255.255.255.255/0/0)
current_peer: 209.165.201.1


#pkts encaps: 1110, #pkts encrypt: 1110, #pkts digest: 1110
#pkts decaps: 1111, #pkts decrypt: 1111, #pkts verify: 1111
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 1110, #pkts comp failed: 0, #pkts decomp failed: 0
#pre-frag successes: 0, #pre-frag failures: 0, #fragments created: 0
#PMTUs sent: 0, #PMTUs rcvd: 0, #decapsulated frgs needing reassembly: 0
#TFC rcvd: 0, #TFC sent: 0
#Valid ICMP Errors rcvd: 0, #Invalid ICMP Errors rcvd: 0
#send errors: 0, #recv errors: 0

local crypto endpt.: 192.0.2.1/500, remote crypto endpt.: 209.165.201.1/500
path mtu 1500, ipsec overhead 58(36), media mtu 1500
PMTU time remaining (sec): 0, DF policy: copy-df
ICMP error validation: disabled, TFC packets: disabled
current outbound spi: 4B6BEB6C
current inbound spi : D8BA0545

inbound esp sas:
spi: 0xD8BA0545 (3636069701)
SA State: active
transform: esp-des esp-sha-hmac no compression
in use settings ={L2L, Tunnel, IKEv2, }
slot: 0, conn_id: 1515, crypto-map: CSM_outside_map
sa timing: remaining key lifetime (kB/sec): (4101105/21619)
IV size: 8 bytes
replay detection support: Y
Anti replay bitmap:
0xFFFFFFFF 0xFFFFFFFF
outbound esp sas:
spi: 0x4B6BEB6C (1265363820)
SA State: active
transform: esp-des esp-sha-hmac no compression
in use settings ={L2L, Tunnel, IKEv2, }
slot: 0, conn_id: 1515, crypto-map: CSM_outside_map
sa timing: remaining key lifetime (kB/sec): (4239345/21619)
IV size: 8 bytes
replay detection support: Y
Anti replay bitmap:
0x00000000 0x00000001


!--- Check the BGP router summary ---!

ftd1# show bgp summary
BGP router identifier 10.127.248.35, local AS number 100
BGP table version is 43, main routing table version 43
4 network entries using 800 bytes of memory
4 path entries using 320 bytes of memory
2/2 BGP path/bestpath attribute entries using 416 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1536 total bytes of memory
BGP activity 20/16 prefixes, 26/22 paths, scan interval 60 secs

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
209.165.201.1 4 100 494 488 43 0 0 09:01:15 2


!--- Check the BGP neighborship ---!

ftd1# show bgp neighbors

BGP neighbor is 209.165.201.1, context single_vf, remote AS 100, internal link
BGP version 4, remote router ID 10.127.248.36
BGP state = Established, up for 09:01:18
Last read 00:00:52, last write 00:00:12, hold time is 180, keepalive interval is 60 seconds
Neighbor sessions:
1 active, is not multisession capable (disabled)
Neighbor capabilities:
Route refresh: advertised and received(new)
Four-octets ASN Capability: advertised and received
Address family IPv4 Unicast: advertised and received
Multisession Capability:
Message statistics:
InQ depth is 0
OutQ depth is 0

Sent Rcvd
Opens: 1 1
Notifications: 0 0
Updates: 3 3
Keepalives: 484 490
Route Refresh: 0 0
Total: 488 494
Default minimum time between advertisement runs is 0 seconds

For address family: IPv4 Unicast
Session: 209.165.201.1
BGP table version 43, neighbor version 43/0
Output queue size : 0
Index 19
19 update-group member
Sent Rcvd
Prefix activity: ---- ----
Prefixes Current: 2 2 (Consumes 160 bytes)
Prefixes Total: 2 2
Implicit Withdraw: 0 0
Explicit Withdraw: 0 0
Used as bestpath: n/a 2
Used as multipath: n/a 0

Outbound Inbound
Local Policy Denied Prefixes: -------- -------
Bestpath from this peer: 2 n/a
Invalid Path: 1 n/a
Total: 3 0
Number of NLRIs in the update sent: max 1, min 0

Address tracking is enabled, the RIB does have a route to 209.165.201.1
Connections established 2; dropped 1
Last reset 09:01:34, due to Peer closed the session of session 1
Transport(tcp) path-mtu-discovery is disabled
Graceful-Restart is disabled


!--- Check the routes learned from BGP ---!

ftd1# sh route bgp

Codes: L - local, C - connected, S - static, 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, V - VPN
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, + - replicated route
Gateway of last resort is 192.0.2.100 to network 0.0.0.0

B 172.16.1.0 255.255.255.0 [200/0] via 209.165.201.1, 00:00:57
B 172.16.2.0 255.255.255.0 [200/0] via 172.16.1.100, 09:01:23

FTD2

!--- Check the IKEv2 sa with remote peer ---!


ftd2# show crypto ikev2 sa

IKEv2 SAs:

Session-id:34, Status:UP-ACTIVE, IKE count:1, CHILD count:1

Tunnel-id Local Remote Status Role
862624945 209.165.201.1/500 192.0.2.1/500 READY RESPONDER
Encr: DES, Hash: SHA96, DH Grp:5, Auth sign: PSK, Auth verify: PSK
Life/Active Time: 86400/32429 sec
Child sa: local selector 209.165.201.1/0 - 209.165.201.1/65535
remote selector 192.0.2.1/0 - 192.0.2.1/65535
ESP spi in/out: 0x4b6beb6c/0xd8ba0545


!--- Check the IPSec sa with remote peer and check the number of encrypts and decrypts---!


ftd2# show crypto ipsec sa
interface: outside
Crypto map tag: CSM_outside_map, seq num: 2, local addr: 209.165.201.1

access-list CSM_IPSEC_ACL_2 extended permit ip host 209.165.201.1 host 192.0.2.1
local ident (addr/mask/prot/port): (209.165.201.1/255.255.255.255/0/0)
remote ident (addr/mask/prot/port): (192.0.2.1/255.255.255.255/0/0)
current_peer: 192.0.2.1


#pkts encaps: 1107, #pkts encrypt: 1107, #pkts digest: 1107
#pkts decaps: 1106, #pkts decrypt: 1106, #pkts verify: 1106
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 1107, #pkts comp failed: 0, #pkts decomp failed: 0
#pre-frag successes: 0, #pre-frag failures: 0, #fragments created: 0
#PMTUs sent: 0, #PMTUs rcvd: 0, #decapsulated frgs needing reassembly: 0
#TFC rcvd: 0, #TFC sent: 0
#Valid ICMP Errors rcvd: 0, #Invalid ICMP Errors rcvd: 0
#send errors: 0, #recv errors: 0

local crypto endpt.: 209.165.201.1/500, remote crypto endpt.: 192.0.2.1/500
path mtu 1500, ipsec overhead 58(36), media mtu 1500
PMTU time remaining (sec): 0, DF policy: copy-df
ICMP error validation: disabled, TFC packets: disabled
current outbound spi: D8BA0545
current inbound spi : 4B6BEB6C

inbound esp sas:
spi: 0x4B6BEB6C (1265363820)
SA State: active
transform: esp-des esp-sha-hmac no compression
in use settings ={L2L, Tunnel, IKEv2, }
slot: 0, conn_id: 1516, crypto-map: CSM_outside_map
sa timing: remaining key lifetime (kB/sec): (4008945/21713)
IV size: 8 bytes
replay detection support: Y
Anti replay bitmap:
0xFFFFFFFF 0xFFFFFFFF
outbound esp sas:
spi: 0xD8BA0545 (3636069701)
SA State: active
transform: esp-des esp-sha-hmac no compression
in use settings ={L2L, Tunnel, IKEv2, }
slot: 0, conn_id: 1516, crypto-map: CSM_outside_map
sa timing: remaining key lifetime (kB/sec): (4239345/21713)
IV size: 8 bytes
replay detection support: Y
Anti replay bitmap:
0x00000000 0x00000001

 
!--- Check the BGP router summary ---!

ftd2# show bgp summary
BGP router identifier 10.127.248.36, local AS number 100
BGP table version is 44, main routing table version 44
3 network entries using 600 bytes of memory
3 path entries using 240 bytes of memory
2/2 BGP path/bestpath attribute entries using 416 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1256 total bytes of memory
BGP activity 20/17 prefixes, 26/23 paths, scan interval 60 secs

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
192.0.2.1 4 100 486 492 44 0 0 08:59:40 2


!--- Check the BGP neighborship ---!


ftd2# show bgp neighbors

BGP neighbor is 192.0.2.1, context single_vf, remote AS 100, internal link
BGP version 4, remote router ID 10.127.248.35
BGP state = Established, up for 08:59:42
Last read 00:00:53, last write 00:00:38, hold time is 180, keepalive interval is 60 seconds
Neighbor sessions:
1 active, is not multisession capable (disabled)
Neighbor capabilities:
Route refresh: advertised and received(new)
Four-octets ASN Capability: advertised and received
Address family IPv4 Unicast: advertised and received
Multisession Capability:
Message statistics:
InQ depth is 0
OutQ depth is 0

Sent Rcvd
Opens: 1 1
Notifications: 0 0
Updates: 2 3
Keepalives: 489 482
Route Refresh: 0 0
Total: 492 486
Default minimum time between advertisement runs is 0 seconds

For address family: IPv4 Unicast
Session: 192.0.2.1
BGP table version 44, neighbor version 44/0
Output queue size : 0
Index 19
19 update-group member
Sent Rcvd
Prefix activity: ---- ----
Prefixes Current: 1 2 (Consumes 160 bytes)
Prefixes Total: 1 2
Implicit Withdraw: 0 0
Explicit Withdraw: 0 0
Used as bestpath: n/a 2
Used as multipath: n/a 0

Outbound Inbound
Local Policy Denied Prefixes: -------- -------
Bestpath from this peer: 2 n/a
Invalid Path: 2 n/a
Total: 4 0
Number of NLRIs in the update sent: max 1, min 0

Address tracking is enabled, the RIB does have a route to 192.0.2.1
Connections established 2; dropped 1
Last reset 08:59:57, due to Peer closed the session of session 1
Transport(tcp) path-mtu-discovery is disabled
Graceful-Restart is disabled


!--- Check the routes learned from BGP ---!

ftd2# show route bgp

Codes: L - local, C - connected, S - static, 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, V - VPN
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, + - replicated route
Gateway of last resort is 209.165.201.100 to network 0.0.0.0

B 10.1.1.0 255.255.255.0 [200/0] via 192.0.2.1, 08:59:46
B 10.1.2.0 255.255.255.0 [200/0] via 10.1.1.100, 08:59:46

Troubleshoot

There is currently no specific troubleshooting information available for this configuration.