# Verifying the Connection Gateway connectivity
<a name="verify-connectivity"></a>

Let's assume that the Connection Gateway host is associated with a DNS name, for instance `dcv.gateway.domain`, and it is listening on TCP port `8443` and UDP port `8443`. We can use the `nc` command to test the connectivity of our gateway.

**To check if the Connection Gateway is reacheable with TCP**  
Use the following command:

```
$ nc -vz dcv.gateway.domain 8443
```

**To check if the Connection Gateway is reacheable with UDP**  
Use the following command:

```
$ nc -uvz dcv.gateway.domain 8443
```

**Note**  
**Note:** The `nc -uvz` command can only confirm UDP connectivity failure when an explicit ICMP error (e.g., "Connection refused") is returned. If packets are silently dropped (e.g., by security groups or firewalls), the command may still report success. A successful result from this command does not guarantee that UDP traffic can reach the DCV Connection Gateway.