Troubleshooting tools

Use these tools to help investigate and resolve issues.


Ping is a software utility that you can use to test if one machine can reach another. It returns the time that it takes for a message to go from the host machine to the destination machine and back again.


ping <destination>

Sample output:

root@Access Gateway ~]# ping PING localhost ( 56(84) bytes of data. 64 bytes from ( icmp_seq=1 ttl=64 time=0.033 ms . . . 64 bytes from ( icmp_seq=5 ttl=64 time=0.048 ms ^C --- Access Gateway ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4479ms rtt min/avg/max/mdev = 0.033/0.042/0.048/0.006 ms

When there's no response from the target host, most implementations of ping display nothing, or periodically print notifications about timing out. The following ping outputs indicate that there may be a problem:

  • H, !N, or !P: host, network, or protocol unreachable

  • S: source route failed

  • T: return time in milliseconds

  • F: fragmentation needed

  • U or !W: destination network or host is unknown

  • I: source host is isolated

  • A: communication with destination network administratively prohibited

  • Z: communication with destination host administratively prohibited

  • Q: for this ToS, the destination network is unreachable

  • X: communication administratively prohibited

  • V: host precedence violation

  • C: precedence cutoff in effect

When an error occurs, the target host or an intermediate router returns an ICMP error message, such as "host unreachable" or "TTL exceeded in transit". These messages include the first eight bytes of the original message (in this case, the header of the ICMP echo request, which includes the quench value). This enables the ping utility to match responses to the originating queries.

NS Lookup

nslookup is a network administration tool used to query the Domain Name System (DNS) to obtain domain name, IP address mapping, or other DNS records.


nslookup [-option] [name | -] [server]

See your nslookup documentation for more details on available options.

Sample output:

[root@localhost ~]# nslookup Server: Address: Non-authoritative answer: canonical name = Name: Address: Name: Address:

The following output provides an example of when nslookup fails to find the DNS record:

[root@localhost ~]# nslookup Server: Address: ** server can't find NXDOMAIN


The telnet command is used for interactive communication with another host using the TELNET protocol. It begins in command mode where it prints a telnet command prompt (telnet>).

Usage:telnet <host> <port>

Sample output of a successful connection:

[root@localhost ~]# telnet 443 Trying Connected to Escape character is '^]'. ^C Connection closed by foreign host.`

Sample output of a failed connection:

[root@localhost ~]# telnet 445 Trying telnet: connect to address Connection refused

In the example, the host is listening on port 443, but not on port 445.

If telnet is not available on Windows, it can be enabled using these steps:

  1. Click Start > Control Panel.

  2. Click Programs and Features.

  3. Click Turn Windows features on or off.

  4. In the Windows Features dialog box, select the Telnet Client option.

  5. Click OK. The system installs the appropriate files. This takes a few moments to complete.

The nc (or netcat) utility is used for many tasks involving TCP, UDP, or UNIX-domain sockets. It can open TCP connections, send UDP packets, listen on arbitrary TCP and UDP ports, scan ports, and deal with both IPv4 and IPv6. Unlike telnet, nc scripts well and separates error messages into standard errors instead of sending them to standard output like telnet does.


nc [options] <host> <port>


Similar to telnet, nc can also be used to validate whether a host is listening on a specified port.

The following are examples of output of both successful and failed connections:

Successful connection:

[root@Access Gateway ~]# nc -v -z -w 1 443 Connection to 443 port [tcp/https] succeeded!

Failed Connection:

[root@Access Gateway ~]# nc -v -z -w 1 445 nc: connect to port 445 (tcp) failed: Connection refused

nc is only available on Unix, Linux, and Mac operating systems.

Access Gateway sample header application

The sample header application is bundled with Access Gateway and can be used to validate the state of the environment and identify issues. You can perform the following tests using the sample header application to identify the root cause of some issues.

No. Component to Validate Validation Steps


Connectivity with Okta

  1. Add/Edit an application in Access Gateway.

  2. Access Gateway fails to create/save application if it fails to connect to Okta.


Okta API token

  1. Add/Edit an application in Access Gateway.

  2. Access Gateway reports an error if Okta API key isn't active.


Okta attributes

  1. Add/Edit the sample header app in Access Gateway.

  2. Add the required attribute in the Attributes tab, and pass it to the header.

  3. Open the sample header app and validate the value of the attribute.


Access Gateway

  1. Open the sample header application.

  2. This should redirect you to Okta for authentication (if an Okta session doesn't exist and the policy is set to protect the app).

  3. Any discrepancy in application flow points to an issue in the environment.


Application in Okta

This can be tested in two ways.

Application in Okta:

  1. Sign in to Okta.

  2. Click the application.

  3. This should redirect you to the application. If it doesn't, there's an issue in the environment.

Application URL in Access Gateway:

  1. Sign in to the Access Gateway Admin UI console.

  2. Go to the Applications tab.

  3. Right-click the Goto application button.

  4. If using Chrome or Firefox, click Copy link address. For Safari, click Copy Link and for Internet Explorer, click Copy shortcut.

  5. Paste the URL in the address bar, and press Enter.

  6. This takes you to Okta for authentication before proceeding to the application. If you aren't directed to the application after authentication, there's an issue with the environment.


Application in Access Gateway

  1. Open the public URL configured in Access Gateway Admin UI console for the application in a browser window.

  2. This should take you to Okta for authentication before proceeding to the application. If you aren't directed to the application after authentication, there's an issue with the environment.