Microtronix Access Serial-TCP/IP Converter
3.4.1 Verifying IP Network
Use ping from another station on the IP network to verify the Access is reachable. Sometimes ARP
cache tables are obsolete and need refreshing after an IP change.
The LAN led on the front panel or rear RJ45 connector led will blink when there is activity on the
Ethernet port.
If the PC used for configuration is still able to reach the Access, use telnet or ssh to connect to the
command line interface. If the unit has been pre-configured for console access on the Console port,
you may use a terminal emulator to connect a PC COM port to the console using 9600-N-8-1. Login
using user name “root” and password “f0adA” (0=zero).
Enter the command “
ifconfig eth0
” to view the status and statistics of the Ethernet interface.
Use ping to test the connection to the default gateway or another station on the IP network. Enter the
command “ping a.b.c.d”, where a.b.c.d is the IP address in dotted notation.
To test the connectivity to a remote IP host that will be connecting to or receiving connections from the
Access, use ping to verify reachability.
3.4.2 Monitoring IP Network
Sometimes tracing an the IP interface may be necessary to determine a problem. The standard
tcpdump utility is provided for this purpose. To run the tcpdump utility, make a telnet connection from a
PC to connect to the Access command line interface. Respond to the login request with the default
username “root” and password “f0adA” (0=zero). At the “#” prompt, enter the “tcpdump” command. It
can be entered with a number of command line options. Use the “-h” option to see a list of all available
options. The normal syntax is:
tcpdump i INTERFACE w OUTPUT_FILE EXPRESSION
To stop tcpdump, type control-C (Ctrl+C). The file can be copied to a PC using FTP or SFTP for
display and analysis using Wireshark (Ethereal). File transfer programs like FileZilla or WinSCP may
be used to retrieve the file.
For example, to monitor TCP port 102 on the Ethernet interface, and record the output into a file:
tcpdump i eth0 w /tmp/tcpdump.pcap tcp port 102
The other possible interface is the loopback interface sometimes used for internal connections:
i lo
For extended monitoring, the output file may also be written to a USB-mounted flash drive (formatted
VFAT-32) by using the path:
w /mnt/usb1/tcpdump.pcap
When the file is completed, the drive may be removed safely by entering the command:
umount
/mnt/usb1/
Other expressions may be used like a remote IP address:
ip host 10.1.1.24
Care must be taken to
NOT
use an expression that would monitor the initiating telnet session.
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