最後更新: 2018-07-24

Echo Port

echo            7/tcp

echo            7/udp

安裝

yum install xinetd

安裝後會有兩個 config file

• echo-dgram
• echo-stream

# There's a UDP echo service as well

/etc/xinetd.d/echo-dgram

...

/etc/xinetd.d/echo-stream

service echo
{
        disable         = no
        id              = echo-stream
        type            = INTERNAL
        wait            = no
        socket_type     = stream
        #only_from       =
}

# Enable service

systemctl restart xinetd

systemctl enable xinetd

# Local test

telnet localhost echo

# firewall

firewall-cmd --add-rich-rule='rule family="ipv4" source address="x.x.x.x" port port="7" protocol="tcp" accept'