Etherlite Rlogin Guide

Etherlite Rlogin Guide

Most Unix systems have an rlogin client which you can use to login to the EtherLite Products. The EtherLite does not prompt for a username and does not require a password. Below is an example of how to login to a EL-32. In this example, the EL-32 has an IP address of 192.168.2.10, and in our /etc/host file it has a name of el10.

rlogin 192.168.2.10

Linux requires the full path for rlogin:

/usr/bin/rlogin 192.168.2.10

Some implementations of rlogin require you to have an entry in your /etc/host file. You will typically receive a "host not found" or "unknown host" error message if this is the case. To correct the problem, you will need to add an entry to your /etc/hosts file, associating a name with the IP address. Once you have done this, you can then rlogin to the Etherlite using the given name or the IP address.

To get a list of the command supported by Etherlite Rlogin server, enter "help". Below is a list of the commands currently supported(all commands are case sensitive).

 

? help
 
 exit         - Close rlogin connection
 help         - This display
 hosttab      - Display the authorized host table
 line         - Display info about a line
 rstats       - Reset ethernet stats
 sockets      - Display socket info
 stats        - Display ethernet stats
 ver          - Version info about the unit


The "ver" command returns version information along with configuration information about the unit.

? ver

 Product:  EL-32
 FW Ver:   V1.7
 
 Ethernet:  00:A0:E7:00:32:98
 IP:        192.168.2.10
 GW IP:     0.0.0.0
 SN Mask:   255.255.0.0
 Lease:     0xFFFFFFFF
 Boot Host: 192.168.2.100
 Bootfile:  el32.prm
 ICMP error (303) getting Bootfile: destination unreachable

The meaning of most of these items is obvious. However, "Lease" refers to a DHCP lease time. A value of 0xFFFFFFFF indicates that no lease is in effect. In other words, the unit got its IP address from a BOOTP server, or a DHCP server was configured to give the unit an infinite lease. Any other value indicates that a DHCP Lease is in effect. The value of "Lease" is the time in seconds remaining on the lease.

"Boot Host" is the IP address of the host that served the unit its IP address. This will also be the host that the unit attempts to TFTP a firmware file from.

"Bootfile" is the filename that the host passed to the unit in the BOOTP response. If the host did not supply a bootfile, the unit will default a {productname}.prm Bootfile.

The final line is a TFTP status line. The Etherlite will always attempt to download a bootfile from the Boot Host. Often, this will result in a ICMP error as shown above. This error is caused by the TFTP server being disabled on the Boot Host. This in not a cause for concern unless you are trying to update the firmware in your etherlite unit. Most systems have their TFTP server disabled for security reasons. Other messages you might see are:

"Access violation"   - indicates a permissions problem at the host.
"File not found",    - bootfile could not be found at the host.
"incorrect bootfile" - the unit downloaded the file, but determined that the file was for a different etherlite product.
"checksum error"     - the unit downloaded the file, but it failed the checksum test.
"timeout"            - the host failed to respond within 30 seconds.


The "stats" command dumps networking statistics.

? stats
           --- Ethernet Transmit Stats ---
total pkts   0000215313
underflow    0000000000      one retry    0000000000
late collis  0000000000      more retries 0000000003
deferred     0000000104      retry limit  0000000000
lost carrier 0000000000      defer limit  0000000000
 
     --- Ethernet Receive Stats ---
total pkts   0000132715      runt pkts    0000000000
overflow     0000000000      collisions   0000000000
late collis  0000000000      jabber err   0000000000
fraiming err 0000000000      babble err   0000000000
fcs err      0000000000      missed pkts  0000000000
oversize pkt 0000000000      can''''t RCV    0000000000
no frames    0000000000
     --- IP Receive Stats ---
total frames 0000131093      fragmented   0000000000
bad chksum   0000000000      -reassembled 0000000000
bad address  0000010041      -discarded   0000000000

Most of these items are common ethernet statistics. However, several need explanation. The "no frames" item indicates the number of times the firmware ran out of ethernet memory buffers and had to wait until one became available. The "can''''t RCV" indicates how many times receive data was lost due to the "no frames" condition. The "bad address" item counts how many IP frames were received by the unit that were not addressed to the unit. This is not really an error condition, and this number may be quite high if the network has a lot of broadcasting going on. The "fragmented", "-reassembled" and "-discarded" items refer to IP fragmentation, which can occur when IP packets are traversing a WAN.

It is common to see some number of errors under the Ethernet Transmit and Receive Statistics. However, anytime you see a high number of errors when compared to the "total pkts" field, should be cause for concern. For example, you will from time to time get an "fcs err" (frame checksum). However if 50% of your total packets have a "fcs err", you have a problem.

The "sockets" command shows the state of active TCP sockets in the unit.

? sockets
               remote local
remote ip       port  port    state       sRTT   sMDEV
--------------- ----- ----- ------------ ------- -------
192.9.200.1     01023 00513 ESTABLISHED  01488ms 01328ms
0.0.0.0         00000 00771 LISTEN       00000ms 02880ms
192.9.200.25    01031 00771 ESTABLISHED  01104ms 00112ms

The local port column indicates the socket type. The value 513 is the Rlogin socket connection, and 771 is the RealPort driver. Etherlites which still use the legacy Etherlite driver will have a local port value of 10001 rather than 771.

The two fields on the right, sRTT and sMDEV are standard TCP statistics. sRTT is the smoothed round-trip time. sMDEV is the smoothed mean deviation from the round-trip time. Round-trip time is the time it takes the host to acknowledge a packet of data sent to it. The sum of sRTT and sMDEV is a good indication of network latency. Note in the above example there are some pretty high numbers. This example was taken from a unit running across an overloaded WAN segment. On a typical LAN segment, the sRTT number would be around 30ms to 40ms.

The "hosttab" command displays the Authorized Host List sent to the unit by the BOOTP server or DHCP server. Below is an example of what you will see when nothing has been entered. For more information about the Authorized Host List, you can download a white paper from our website.

? hosttab
  
 Mask            IP
 --------------- ---------------
 0.0.0.0         0.0.0.0

The "line" command displays state information about a single line. Below is an example of a line that is not enabled by any host and another that is.

? line 0
         
 ---- Line  0 ----
 Settings: 8,None,1
 Tx baud: 9600
 Rx baud: 9600
 DCD,DSR,CTS: 000
 DTR,RTS: 00
 Rx Soft Fctrl: 1h
 RTS Fctrl: 0h
 Tx Soft Fctrl: 1h
 CTS Fctrl: 0h
 Xon/Xoff char: 11h, 13h
 Tx Queue: 0
 Rx Queue: 0
 I/O State: 0h
 Status: disabled
? line 6
         
 ---- Line  6 ----
 Settings: 8,None,1
 Tx baud: 9600
 Rx baud: 9600
 DCD,DSR,CTS: 000
 DTR,RTS: 11
 Rx Soft Fctrl: 1h
 RTS Fctrl: 0h
 Tx Soft Fctrl: 1h
 CTS Fctrl: 0h
 Xon/Xoff char: 11h, 13h
 Tx Queue: 0
 Rx Queue: 0
 I/O State: 0h
 Status: enabled by host 192.9.200.25


The "DCD,DSR,CTS:" item shows the state of the modem input signals. The "DTR,RTS" item shows the state of the output signals. A "1" for the value of the Soft Fctrl items indicates that software flow control is enabled. A "80" value for the RTS and CTS Fctrl items indicate that hardware flow control is enabled. The "Tx Queue" and "Rx Queue" items give the amount of data in the transmit and receive buffers. The "I/O State" item is unique to each type of Etherlite product, and is used in firmware debug.


Last updated: Aug 08, 2017

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