Enable telnet and FTP services in Linux (RedHat)

The telnet package must be installed when the telnet service is enabled in Linux.

Run the following command to check whether the Telnet package is installed:
Rpm-Qa Telnet

[Root @ localhost xinetd. d] # rpm-Qa Telnet
Telnet-0.17-39.el5

If yes, the telnet version is displayed. If Not Installed
Application-Add/delete programs to install the Telnet software package.

After installing telnet, You need to modify two configuration files.
[Root @ localhost etc] # cd/etc/xinetd. d
[Root @ localhost xinetd. d] # ls
Chargen-dgram discards-dgram ekrb5-telnet ktalk time-stream
Chargen-stream discard-stream gssftp rsync
CVS echo-dgram Klogin tcpmux-Server
Daytime-dgram echo-stream krb5-telnet TFTP
Daytime-stream eklogin kshell time-dgram
View profiles: ekrb5-telnet, krb5-telnet
The ekrb5-telnet configuration Telnet encrypted connection is generally set to off
View the content of two configuration files
[Root @ localhost xinetd. d] # krb5-telnet more
# Default: Off
# Description: The authenticated Telnet Server accepts normal Telnet sessions ,/
# But can also use Kerberos 5 authentication.
Service telnet
{
Disable = No
Flags = Reuse
Socket_type = stream
Wait = No
User = root
Server =/usr/Kerberos/sbin/telnetd
Log_on_failure + = userid
}
[Root @ localhost xinetd. d] # ekrb5-telnet more
# Default: Off
# Description: The authenticated Telnet Server accepts only Telnet sessions ,/
# Which use Kerberos 5 authentication and encryption.
Service telnet
{
Disable = Yes
Flags = Reuse
Socket_type = stream
Wait = No
User = root
Server =/usr/Kerberos/sbin/telnetd
Server_args =-e
Log_on_failure + = userid
}
Set disable in the erkb5-telnet file to disabled (yes ):
[Root @ localhost xinetd. d] # chkconfig ekrb5-telnet off
Set disable in krb5-telnet to available (NO );
[Root @ localhost xinetd. d] # chkconfig krb5-telnet on
Check whether the configuration file has the same attributes as the one shown above.
Restart the xinetd service.
[Root @ localhost xinetd. d] # service xinetd restart
Stop xinetd: [OK]
Start xinetd: [OK]
You can use Telnet to connect to a Linux IP address.
[Root @ localhost xinetd. d] # IP ADDR
1: Lo: <loopback, up, lower_up> MTU 16436 qdisc noqueue
Link/loopback 00: 00: 00: 00: 00: 00 BRD 00: 00: 00: 00: 00: 00
Inet 127.0.0.1/8 Scope host Lo
Inet6: 1/128 scope host
Valid_lft forever preferred_lft forever
2: eth0: <broadcast, multicast, up, lower_up> MTU 1500 qdisc pfifo_fast qlen 1000
Link/ether 00: 0C: 29: Fe: de: 56 brd ff: FF
Inet 192.168.1.104/24 BRD 192.168.1.255 scope global eth0
Inet6 fe80: 20c: 29ff: Fefe: de56/64 scope Link
Valid_lft forever preferred_lft forever
3: sit0: <noarp> MTU 1480 qdisc Noop
Link/Sit 0.0.0.0 BRD 0.0.0.0
The inet in 2 is followed by the IP address. In this example, the IP address is 192.168.1.104.
The process for enabling the FTP service is roughly the same as that for telnet.
[Root @ localhost xinetd. d] # More gssftp
# Default: Off
# Description: The specified FTP Server accepts FTP connections/
# That can be authenticated with Kerberos 5.
Service ftp
{
Flags = Reuse
Socket_type = stream
Wait = No
User = root
Server =/usr/Kerberos/sbin/ftpd
Server_args =-l
Log_on_failure + = userid
Disable = No
}

Run the VI gssftp command to modify the gssftp file:
Server_args =-l-A ==> server_args =-l
Disable = yes => disable = No
Save the modification and exit. Restart the xinetd service.
Service xinetd restart can use the FTP service