Disabling RHEL services

Last Updated : Mar 13, 2021 |

Custom scripts or other custom integration added after the installation as part of an Avaya Professional Services offer might require one or more of these services. The following network services are allowed to be disabled when not required for customized integration:

  • Chargen (19/tcp, 19/udp)

  • Daytime (13/tcp, 13/udp)

  • Discard (9/tcp, 9/udp)

  • Echo (network echo - 7/tcp, 7/udp)

  • Finger (79/tcp)

  • Font Server (7100/tcp)

  • FTP (inbound - 21/tcp)

  • Kerberos V5 Warning Message Daemon (88/tcp, 88/udp)

  • Name (42/udp)

  • NFS Client (lockd - 4045/tcp, 4045/udp)

  • NFS Server (2049/tcp, 2049/udp)

  • NISClient

  • Printer (Network printing services, local printing is enabled - 515/tcp)

  • Rexec (512/tcp)

  • Rlogin (513/tcp)

  • Rsh (514/tcp)

  • Sendmail (inbound - 25/tcp)

  • Spray (100012/tcp, 100012/udp)

  • Syslog (514/udp)

  • Talk (517/tcp)

  • Time Service (37/tcp, 37/udp)

  • UUCP Network services (540/tcp)

  • Wall

Disabling some of these services may interfere with network-related troubleshooting activities such as echo and network monitoring tools.

Telnet (23/tcp) cannot be disabled even if ssh is configured for clients, but it can be restricted to the local host so that it does not respond externally.