Hello @mohammed shankar !
Welcome to Microsoft QnA!
For a Radius Server to work you can do it only with Azure Domain Services
Azure AD Domain Services provides managed domain services such as domain join, group policy, LDAP, and Kerberos/NTLM authentication. You need to enable AAD DS in your Azure environment.
Azure AD does not support the Radius implementation
If you could provide more details on the purpose we may provide a way but in general LDAP is not supported on Azure AD - Entra ID , only via Azure Domain Services
https://azure.microsoft.com/en-us/products/active-directory-ds
https://learn.microsoft.com/en-au/azure/active-directory-domain-services/tutorial-configure-ldaps
I hope this helps!
Kindly mark the answer as Accepted and Upvote in case it helped!
Regards