No data on telnet connection

2011-11-30
2013-04-01
  • I am able to connect to ttyS0 with minicom 112500 8N1 and get a login prompt.
    But when I telnet to ttyS0 via configured port 2000 I see a connection in ser2net but there is no data on the telnet console.

    What am I doing wrong?

    root@PC3:~# ps auxww | grep ser2net | grep -v grep
    root     32479  0.0  0.0   1908   548 ?        S    15:46   0:00 /usr/sbin/ser2net -p 9999 -c /etc/ser2net.conf -P /var/run ser2net.pid -u
    root@PC3:~#

    -> showport 2000
    TCP Port 2000
      enable state: telnet
      timeout: 600
      connected to (or last connection): 10.15.1.114:38068
      device: /dev/ttyS0
      device config: 115200 1STOPBIT 8DATABITS NONE
      device controls: RTSHI DTRHI
      tcp to device state: waiting input
      device to tcp state: waiting input
      bytes read from TCP: 0
      bytes written to TCP: 71
      bytes read from device: 0
      bytes written to device: 0

    TRACEFILE:tracenm:/tmp/trace.log
    BANNER:banner:\r\nser2net port \p device \d  (Ubuntu Lab-PC3)\r\n\r\n

    2000:telnet:600:/dev/ttyS0:115200 8DATABITS NONE 1STOPBIT -LOCAL -XONXOFF -RTSCTS banner
    2001:telnet:600:/dev/ttyS1:115200 8DATABITS NONE 1STOPBIT banner
    2002:telnet:600:/dev/ttyS2:115200 8DATABITS NONE 1STOPBIT banner
    2003:telnet:600:/dev/ttyS3:115200 8DATABITS NONE 1STOPBIT banner

    Here is the telnet connection
    $ telnet 10.16.1.13 2000
    Trying 10.16.1.13…
    Connected to 10.16.1.13.
    Escape character is '^]'.


    tcpdump shows the initial connection to port 2000 but after there is no data going back to the other pc.
    Typing and hitting enter in telnet does not send any data across.