Cisco does not recommend any specific set of hardening guidelines. However, if you consider hardening the system, the following hardening guidelines should be considered for each host platform:

• Red Hat 6:

  https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/pdf/

  Security_Guide/Red_Hat_Enterprise_Linux-6-Security_Guide-en-US.pdf

• Red Hat 7:

  https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/pdf/

  Security_Guide/Red_Hat_Enterprise_Linux-7-Security_Guide-en-US.pdf

• Windows Server 2012:

  https://technet.microsoft.com/en-us/security/jj720323.aspx

• NSA hardening guide collection:

  https://www.nsa.gov/ia/mitigation_guidance/security_configuration_guides/operating_systems.shtml

Note	The above links reference external websites and Cisco is not responsible for keeping them up-to-date. They are provided for reference only. If you find that the content is outdated or if you cannot access the links, please contact the website owner for updated information.