# Troubleshoot AWS Site-to-Site VPN connectivity with a Juniper ScreenOS customer gateway device
When you troubleshoot the connectivity of a Juniper ScreenOS-based 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 and IPsec
Use the following command. The response shows a customer gateway device with IKE configured correctly.
```
ssg5-serial-> get sa
```
```
total configured sa: 2
HEX ID Gateway Port Algorithm SPI Life:sec kb Sta PID vsys
00000002< 72.21.209.225 500 esp:a128/sha1 80041ca4 3385 unlim A/- -1 0
00000002> 72.21.209.225 500 esp:a128/sha1 8cdd274a 3385 unlim A/- -1 0
00000001< 72.21.209.193 500 esp:a128/sha1 ecf0bec7 3580 unlim A/- -1 0
00000001> 72.21.209.193 500 esp:a128/sha1 14bf7894 3580 unlim A/- -1 0
```
You should see one or more lines containing a remote address of the remote gateway that is specified in the tunnels. The `Sta` value should be `A/-` and `SPI` should be a hexadecimal number other than `00000000`. Entries in other states indicate that IKE is not configured properly.
For further troubleshooting, enable the IKE trace options (as recommended in the example configuration file).
## 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.
```
ssg5-serial-> get interface tunnel.1
```
```
Interface tunnel.1:
description tunnel.1
number 20, if_info 1768, if_index 1, mode route
link ready
vsys Root, zone Trust, vr trust-vr
admin mtu 1500, operating mtu 1500, default mtu 1500
*ip 169.254.255.2/30
*manage ip 169.254.255.2
route-deny disable
bound vpn:
IPSEC-1
Next-Hop Tunnel Binding table
Flag Status Next-Hop(IP) tunnel-id VPN
pmtu-v4 disabled
ping disabled, telnet disabled, SSH disabled, SNMP disabled
web disabled, ident-reset disabled, SSL disabled
OSPF disabled BGP enabled RIP disabled RIPng disabled mtrace disabled
PIM: not configured IGMP not configured
NHRP disabled
bandwidth: physical 0kbps, configured egress [gbw 0kbps mbw 0kbps]
configured ingress mbw 0kbps, current bw 0kbps
total allocated gbw 0kbps
```
Make sure that you see `link:ready`, and that the `IP` 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.
```
ssg5-serial-> ping 169.254.255.1
```
```
Type escape sequence to abort
Sending 5, 100-byte ICMP Echos to 169.254.255.1, timeout is 1 seconds
!!!!!
Success Rate is 100 percent (5/5), round-trip time min/avg/max=32/32/33 ms
```
For further troubleshooting, review the configuration.
## BGP
Run the following command.
```
ssg5-serial-> get vrouter trust-vr protocol bgp neighbor
```
```
Peer AS Remote IP Local IP Wt Status State ConnID Up/Down
--------------------------------------------------------------------------------
7224 169.254.255.1 169.254.255.2 100 Enabled ESTABLISH 10 00:01:01
7224 169.254.255.5 169.254.255.6 100 Enabled ESTABLISH 11 00:00:59
```
The state of both BGP peers should be `ESTABLISH`, which means that the BGP connection to the virtual private gateway is active.
For further troubleshooting, use the following command, replacing `169.254.255.1` with the inside IP address of your virtual private gateway.
```
ssg5-serial-> get vr trust-vr prot bgp neigh 169.254.255.1
```
```
peer: 169.254.255.1, remote AS: 7224, admin status: enable
type: EBGP, multihop: 0(disable), MED: node default(0)
connection state: ESTABLISH, connection id: 18 retry interval: node default(120s), cur retry time 15s
configured hold time: node default(90s), configured keepalive: node default(30s)
configured adv-interval: default(30s)
designated local IP: n/a
local IP address/port: 169.254.255.2/13946, remote IP address/port: 169.254.255.1/179
router ID of peer: 169.254.255.1, remote AS: 7224
negotiated hold time: 30s, negotiated keepalive interval: 10s
route map in name: , route map out name:
weight: 100 (default)
self as next hop: disable
send default route to peer: disable
ignore default route from peer: disable
send community path attribute: no
reflector client: no
Neighbor Capabilities:
Route refresh: advertised and received
Address family IPv4 Unicast: advertised and received
force reconnect is disable
total messages to peer: 106, from peer: 106
update messages to peer: 6, from peer: 4
Tx queue length 0, Tx queue HWM: 1
route-refresh messages to peer: 0, from peer: 0
last reset 00:05:33 ago, due to BGP send Notification(Hold Timer Expired)(code 4 : subcode 0)
number of total successful connections: 4
connected: 2 minutes 6 seconds
Elapsed time since last update: 2 minutes 6 seconds
```
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. This command applies to ScreenOS version 6.2.0 and higher.
```
ssg5-serial-> get vr trust-vr protocol bgp rib neighbor 169.254.255.1 advertised
```
```
i: IBGP route, e: EBGP route, >: best route, *: valid route
Prefix Nexthop Wt Pref Med Orig AS-Path
--------------------------------------------------------------------------------------
>i 0.0.0.0/0 0.0.0.0 32768 100 0 IGP
Total IPv4 routes advertised: 1
```
Additionally, ensure that you're receiving the prefix that corresponds to your VPC from the virtual private gateway. This command applies to ScreenOS version 6.2.0 and higher.
```
ssg5-serial-> get vr trust-vr protocol bgp rib neighbor 169.254.255.1 received
```
```
i: IBGP route, e: EBGP route, >: best route, *: valid route
Prefix Nexthop Wt Pref Med Orig AS-Path
--------------------------------------------------------------------------------------
>e* 10.0.0.0/16 169.254.255.1 100 100 100 IGP 7224
Total IPv4 routes received: 1
```