Red Hat Enterprise Linux 5 Administration Unleashed

588scriptsscriptsAwk, 249Bash, 239conditionals, 244-245echo command, 241-242executing commands, 240-242loops, 245-246running, 243-244variables, 242initialization scripts, 119-120Perl, 247Python, 247Sed, 248-249sctp match extension (IPTables), 491sealert command, 472search statements, named.conf files(BIND), 342secondary servers, 340SecureListen directive (global configurationdirectives), 331secure_email_list_enable directive (anonymousFTP), 390security. See also firewalls; SELinux(Security-Enhanced Linux)email servers, SSL encryption, 372-373ExecShield, 547-549file transfersscp command, 359sftp command, 360remote logins via OpenSSHallowing connections, 355-356establishing SSH tunnels, 366logging connections, 366passphrase creation, 361-362port forwarding, 365-366remembering phrases, 363remote system logins, 358-359remotely executing commands, 359retaining server authentication keys afterreinstalling, 356-357secure file transfers, 359-361server configuration, 356-357X11 forwarding, 364troubleshooting, 558security contexts (SELinux), 469modifying, 470-474multiple file sharing protocols, 475permanent changes, 475viewing, 470Security tab (Server Settings dialog), 307-308Sed scripts, 248-249SELinux (Security-Enhanced Linux), 463Apache HTTP server, 327disabling, 468FTP servers, 387-388mode selection, 464-465NFS, 294NIS, 257policiescustomizing, 466-467selecting, 466Samba, 304security contexts, 469modifying, 470-474mulitple file sharing protocols, 475permanent changes, 475viewing, 470Troubleshooting Tool, 468-469selinux command (kickstart), 43SendmailDovecot, 374-377/etc/mail directory, 370-371mail server configurationallowing connections, 377-378/etc/aliases configuration file, 371