Troubleshooting Cisco IOS customer gateway device connectivity
When you troubleshoot the connectivity of a Cisco customer gateway device, consider four things: IKE, IPsec, the tunnel, and BGP. You can troubleshoot these areas in any order, but we recommend that you start with IKE (at the bottom of the network stack) and move up.
IKE
Use the following command. The response shows a customer gateway device with IKE configured correctly.
router#
show crypto isakmp sa
IPv4 Crypto ISAKMP SA
dst src state conn-id slot status
192.168.37.160 72.21.209.193 QM_IDLE 2001 0 ACTIVE
192.168.37.160 72.21.209.225 QM_IDLE 2002 0 ACTIVE
You should see one or more lines containing an src
value for the remote
gateway that is specified in the tunnels. The state
should be
QM_IDLE
and status
should be ACTIVE
. The
absence of an entry, or any entry in another state, indicate that IKE is not
configured properly.
For further troubleshooting, run the following commands to enable log messages that provide diagnostic information.
router#
term mon
router#
debug crypto isakmp
To disable debugging, use the following command.
router#
no debug crypto isakmp
IPsec
Use the following command. The response shows a customer gateway device with IPsec configured correctly.
router#
show crypto ipsec sa
interface: Tunnel1
Crypto map tag: Tunnel1-head-0, local addr 192.168.37.160
protected vrf: (none)
local ident (addr/mask/prot/port): (0.0.0.0/0.0.0.0/0/0)
remote ident (addr/mask/prot/port): (0.0.0.0/0.0.0.0/0/0)
current_peer 72.21.209.225 port 500
PERMIT, flags={origin_is_acl,}
#pkts encaps: 149, #pkts encrypt: 149, #pkts digest: 149
#pkts decaps: 146, #pkts decrypt: 146, #pkts verify: 146
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 0, #pkts compr. failed: 0
#pkts not decompressed: 0, #pkts decompress failed: 0
#send errors 0, #recv errors 0
local crypto endpt.: 174.78.144.73, remote crypto endpt.: 72.21.209.225
path mtu 1500, ip mtu 1500, ip mtu idb FastEthernet0
current outbound spi: 0xB8357C22(3090512930)
inbound esp sas:
spi: 0x6ADB173(112046451)
transform: esp-aes esp-sha-hmac ,
in use settings ={Tunnel, }
conn id: 1, flow_id: Motorola SEC 2.0:1, crypto map: Tunnel1-head-0
sa timing: remaining key lifetime (k/sec): (4467148/3189)
IV size: 16 bytes
replay detection support: Y replay window size: 128
Status: ACTIVE
inbound ah sas:
inbound pcp sas:
outbound esp sas:
spi: 0xB8357C22(3090512930)
transform: esp-aes esp-sha-hmac ,
in use settings ={Tunnel, }
conn id: 2, flow_id: Motorola SEC 2.0:2, crypto map: Tunnel1-head-0
sa timing: remaining key lifetime (k/sec): (4467148/3189)
IV size: 16 bytes
replay detection support: Y replay window size: 128
Status: ACTIVE
outbound ah sas:
outbound pcp sas:
interface: Tunnel2
Crypto map tag: Tunnel2-head-0, local addr 174.78.144.73
protected vrf: (none)
local ident (addr/mask/prot/port): (0.0.0.0/0.0.0.0/0/0)
remote ident (addr/mask/prot/port): (0.0.0.0/0.0.0.0/0/0)
current_peer 72.21.209.193 port 500
PERMIT, flags={origin_is_acl,}
#pkts encaps: 26, #pkts encrypt: 26, #pkts digest: 26
#pkts decaps: 24, #pkts decrypt: 24, #pkts verify: 24
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 0, #pkts compr. failed: 0
#pkts not decompressed: 0, #pkts decompress failed: 0
#send errors 0, #recv errors 0
local crypto endpt.: 174.78.144.73, remote crypto endpt.: 72.21.209.193
path mtu 1500, ip mtu 1500, ip mtu idb FastEthernet0
current outbound spi: 0xF59A3FF6(4120526838)
inbound esp sas:
spi: 0xB6720137(3060924727)
transform: esp-aes esp-sha-hmac ,
in use settings ={Tunnel, }
conn id: 3, flow_id: Motorola SEC 2.0:3, crypto map: Tunnel2-head-0
sa timing: remaining key lifetime (k/sec): (4387273/3492)
IV size: 16 bytes
replay detection support: Y replay window size: 128
Status: ACTIVE
inbound ah sas:
inbound pcp sas:
outbound esp sas:
spi: 0xF59A3FF6(4120526838)
transform: esp-aes esp-sha-hmac ,
in use settings ={Tunnel, }
conn id: 4, flow_id: Motorola SEC 2.0:4, crypto map: Tunnel2-head-0
sa timing: remaining key lifetime (k/sec): (4387273/3492)
IV size: 16 bytes
replay detection support: Y replay window size: 128
Status: ACTIVE
outbound ah sas:
outbound pcp sas:
For each tunnel interface, you should see both inbound esp sas
and
outbound esp sas
. Assuming an SA is listed (spi:
0xF95D2F3C
, for example) and the Status
is
ACTIVE
, IPsec is configured correctly.
For further troubleshooting, use the following command to enable debugging.
router#
debug crypto ipsec
Use the following command to disable debugging.
router#
no debug crypto ipsec
Tunnel
First, check that you have the necessary firewall rules in place. For more information, see Firewall rules for your customer gateway device.
If your firewall rules are set up correctly, then continue troubleshooting with the following command.
router#
show interfaces tun1
Tunnel1 is up, line protocol is up
Hardware is Tunnel
Internet address is 169.254.255.2/30
MTU 17867 bytes, BW 100 Kbit/sec, DLY 50000 usec,
reliability 255/255, txload 2/255, rxload 1/255
Encapsulation TUNNEL, loopback not set
Keepalive not set
Tunnel source 174.78.144.73, destination 72.21.209.225
Tunnel protocol/transport IPSEC/IP
Tunnel TTL 255
Tunnel transport MTU 1427 bytes
Tunnel transmit bandwidth 8000 (kbps)
Tunnel receive bandwidth 8000 (kbps)
Tunnel protection via IPSec (profile "ipsec-vpn-92df3bfb-0")
Last input never, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/0 (size/max)
5 minute input rate 0 bits/sec, 1 packets/sec
5 minute output rate 1000 bits/sec, 1 packets/sec
407 packets input, 30010 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
Make sure that the line protocol
is up. Check that the tunnel source IP
address, source interface, and destination respectively match the tunnel
configuration for the customer gateway device outside IP address, interface, and
virtual private gateway outside IP address. Make sure that Tunnel protection
via IPSec
is present. Run the command on both tunnel interfaces. To
resolve any problems, review the configuration and check the physical connections to
your customer gateway device.
Also use the following command, replacing
169.254.255.1
with the inside IP address of
your virtual private gateway.
router#
ping
169.254.255.1
df-bit size 1410
Type escape sequence to abort.
Sending 5, 1410-byte ICMP Echos to 169.254.255.1, timeout is 2 seconds:
Packet sent with the DF bit set
!!!!!
You should see five exclamation points.
For further troubleshooting, review the configuration.
BGP
Use the following command.
router#
show ip bgp summary
BGP router identifier 192.168.37.160, local AS number 65000
BGP table version is 8, main routing table version 8
2 network entries using 312 bytes of memory
2 path entries using 136 bytes of memory
3/1 BGP path/bestpath attribute entries using 444 bytes of memory
1 BGP AS-PATH entries using 24 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
Bitfield cache entries: current 1 (at peak 2) using 32 bytes of memory
BGP using 948 total bytes of memory
BGP activity 4/1 prefixes, 4/1 paths, scan interval 15 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
169.254.255.1 4 7224 363 323 8 0 0 00:54:21 1
169.254.255.5 4 7224 364 323 8 0 0 00:00:24 1
Both neighbors should be listed. For each, you should see a State/PfxRcd
value
of 1
.
If the BGP peering is up, verify that your customer gateway device is advertising the default route (0.0.0.0/0) to the VPC.
router#
show bgp all neighbors
169.254.255.1
advertised-routes
For address family: IPv4 Unicast
BGP table version is 3, local router ID is 174.78.144.73
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Originating default network 0.0.0.0
Network Next Hop Metric LocPrf Weight Path
*> 10.120.0.0/16 169.254.255.1 100 0 7224 i
Total number of prefixes 1
Additionally, ensure that you're receiving the prefix corresponding to your VPC from the virtual private gateway.
router#
show ip route bgp
10.0.0.0/16 is subnetted, 1 subnets
B 10.255.0.0 [20/0] via 169.254.255.1, 00:00:20
For further troubleshooting, review the configuration.