# Troubleshoot AWS Site-to-Site VPN connectivity with a Juniper JunOS customer gateway device
When you troubleshoot the connectivity of a Juniper customer gateway device, consider four things: IKE, IPsec, 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.
```
user@router> show security ike security-associations
```
```
Index Remote Address State Initiator cookie Responder cookie Mode
4 72.21.209.225 UP c4cd953602568b74 0d6d194993328b02 Main
3 72.21.209.193 UP b8c8fb7dc68d9173 ca7cb0abaedeb4bb Main
```
You should see one or more lines containing a remote address of the remote gateway specified in the tunnels. The `State` should be `UP`. The absence of an entry, or any entry in another state (such as `DOWN`), is an indication that IKE is not configured properly.
For further troubleshooting, enable the IKE trace options as recommended in the example configuration file. Then run the following command to print a variety of debugging messages to the screen.
```
user@router> monitor start kmd
```
From an external host, you can retrieve the entire log file with the following command.
```
scp username@router.hostname:/var/log/kmd
```
## IPsec
Use the following command. The response shows a customer gateway device with IPsec configured correctly.
```
user@router> show security ipsec security-associations
```
```
Total active tunnels: 2
ID Gateway Port Algorithm SPI Life:sec/kb Mon vsys
<131073 72.21.209.225 500 ESP:aes-128/sha1 df27aae4 326/ unlim - 0
>131073 72.21.209.225 500 ESP:aes-128/sha1 5de29aa1 326/ unlim - 0
<131074 72.21.209.193 500 ESP:aes-128/sha1 dd16c453 300/ unlim - 0
>131074 72.21.209.193 500 ESP:aes-128/sha1 c1e0eb29 300/ unlim - 0
```
Specifically, you should see at least two lines per gateway address (corresponding to the remote gateway). The carets at the beginning of each line (< >) indicate the direction of traffic for the particular entry. The output has separate lines for inbound traffic ("<", traffic from the virtual private gateway to this customer gateway device) and outbound traffic (">").
For further troubleshooting, enable the IKE traceoptions (for more information, see the preceding section about IKE).
## Tunnel
First, double-check that you have the necessary firewall rules in place. For a list of rules, see [Firewall rules for an AWS Site-to-Site VPN customer gateway device](FirewallRules.md).
If your firewall rules are set up correctly, then continue troubleshooting with the following command.
```
user@router> show interfaces st0.1
```
```
Logical interface st0.1 (Index 70) (SNMP ifIndex 126)
Flags: Point-To-Point SNMP-Traps Encapsulation: Secure-Tunnel
Input packets : 8719
Output packets: 41841
Security: Zone: Trust
Allowed host-inbound traffic : bgp ping ssh traceroute
Protocol inet, MTU: 9192
Flags: None
Addresses, Flags: Is-Preferred Is-Primary
Destination: 169.254.255.0/30, Local: 169.254.255.2
```
Make sure that the `Security: Zone` is correct, and that the `Local` address matches the customer gateway device tunnel inside address.
Next, use the following command, replacing `169.254.255.1` with the inside IP address of your virtual private gateway. Your results should look like the response shown here.
```
user@router> ping 169.254.255.1 size 1382 do-not-fragment
```
```
PING 169.254.255.1 (169.254.255.1): 1410 data bytes
64 bytes from 169.254.255.1: icmp_seq=0 ttl=64 time=71.080 ms
64 bytes from 169.254.255.1: icmp_seq=1 ttl=64 time=70.585 ms
```
For further troubleshooting, review the configuration.
## BGP
Run the following command.
```
user@router> show bgp summary
```
```
Groups: 1 Peers: 2 Down peers: 0
Table Tot Paths Act Paths Suppressed History Damp State Pending
inet.0 2 1 0 0 0 0
Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
169.254.255.1 7224 9 10 0 0 1:00 1/1/1/0 0/0/0/0
169.254.255.5 7224 8 9 0 0 56 0/1/1/0 0/0/0/0
```
For further troubleshooting, use the following command, replacing `169.254.255.1` with the inside IP address of your virtual private gateway.
```
user@router> show bgp neighbor 169.254.255.1
```
```
Peer: 169.254.255.1+179 AS 7224 Local: 169.254.255.2+57175 AS 65000
Type: External State: Established Flags:
Last State: OpenConfirm Last Event: RecvKeepAlive
Last Error: None
Export: [ EXPORT-DEFAULT ]
Options:
Holdtime: 30 Preference: 170 Local AS: 65000 Local System AS: 0
Number of flaps: 0
Peer ID: 169.254.255.1 Local ID: 10.50.0.10 Active Holdtime: 30
Keepalive Interval: 10 Peer index: 0
BFD: disabled, down
Local Interface: st0.1
NLRI for restart configured on peer: inet-unicast
NLRI advertised by peer: inet-unicast
NLRI for this session: inet-unicast
Peer supports Refresh capability (2)
Restart time configured on the peer: 120
Stale routes from peer are kept for: 300
Restart time requested by this peer: 120
NLRI that peer supports restart for: inet-unicast
NLRI that restart is negotiated for: inet-unicast
NLRI of received end-of-rib markers: inet-unicast
NLRI of all end-of-rib markers sent: inet-unicast
Peer supports 4 byte AS extension (peer-as 7224)
Table inet.0 Bit: 10000
RIB State: BGP restart is complete
Send state: in sync
Active prefixes: 1
Received prefixes: 1
Accepted prefixes: 1
Suppressed due to damping: 0
Advertised prefixes: 1
Last traffic (seconds): Received 4 Sent 8 Checked 4
Input messages: Total 24 Updates 2 Refreshes 0 Octets 505
Output messages: Total 26 Updates 1 Refreshes 0 Octets 582
Output Queue[0]: 0
```
Here you should see `Received prefixes` and `Advertised prefixes` listed at 1 each. This should be within the `Table inet.0` section.
If the `State` is not `Established`, check the `Last State` and `Last Error` for details of what is required to correct the problem.
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.
```
user@router> show route advertising-protocol bgp 169.254.255.1
```
```
inet.0: 10 destinations, 11 routes (10 active, 0 holddown, 0 hidden)
Prefix Nexthop MED Lclpref AS path
* 0.0.0.0/0 Self I
```
Additionally, make sure that you're receiving the prefix that corresponds to your VPC from the virtual private gateway.
```
user@router> show route receive-protocol bgp 169.254.255.1
```
```
inet.0: 10 destinations, 11 routes (10 active, 0 holddown, 0 hidden)
Prefix Nexthop MED Lclpref AS path
* 10.110.0.0/16 169.254.255.1 100 7224 I
```