Hello Sharath,
The telnet package is not included in any of the CA-issued OVA images we use for our Gateway appliances, as they ship out of the box as a hardened operating system, meaning many of the default packages in a CentOS or RHEL appliance is not included in the ones we create if they're not necessary or critical in some way to the operation of the actual Gateway application.
If you're wanting to install telnet in your environment, you'll need to find the telnet RPM from a trusted source. That source is entirely up to you, but my advice is to obtain it from an official mirror of the operating system, such as this one for CentOS (the RPM packages should apply to both CentOS and RHEL in this case): http://mirror.csclub.uwaterloo.ca/centos/7/os/x86_64/Packages/
From the link above, you'll find the telnet RPM listed on that page. You can then download it, upload to the Gateway, and install it using the appropriate rpm command.
As this post has to do with help installing a third-party tool (which isn't something we are really responsible for as it can potentially have unintended consequences), I must preface all of the above with the following official statement on third-party tools for use on the Gateway:
When possible, we recommend that you utilize the API Gateway's built-in functionality before installing external applications. When the API Gateway's built-in functionality does not meet your requirements, we permit our customers to install additional applications without terminating or negatively impacting the support agreement between your organization and ours.
As with any change to the API Gateway, we strongly recommend that thorough testing in non-critical environments is carried out before escalating the deployment to more business-critical production systems. Please keep in mind that we may request that this software / application be removed from the system during subsequent support requests where we feel the third-party application may be interfering with the proper operation of the API Gateway.
Lastly, we do not include updates for external applications, tools, or their dependencies in API Gateway patches or platform updates. Upgrading an appliance may cause previously working configurations of your third-party tool to break, and such action would not be supported by CA Technologies. Since we do not provide updates for these external applications, we also do not test them. As such, external applications may create security vulnerabilities in our product that would not be present on a certified API Gateway appliance.
I hope the above helps point you in the right direction to get telnet installed. Good luck! While I can't necessarily walk you through the entire installation since it's a third-party tool, I'll at least be here if you need some guidance.
Sincerely,
Dustin Dauncey
Sr Support Engineer, Global Customer Success
Email: Dustin.Dauncey@ca.com
Phone: +1 800 225 5224, 48385
Phone if outside North America: https://tinyurl.com/CAContactSupport
CA API Management Community: https://tinyurl.com/CAAPIMCommunity