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Full Discussion: expect telnet unexpected delays
Special Forums UNIX and Linux Applications Infrastructure Monitoring expect telnet unexpected delays Post 302315601 by kp2a on Tuesday 12th of May 2009 10:35:43 PM
Old 05-12-2009
expect telnet unexpected delays
I must automatically monitor and manage a large number of boxes on our network.

I have been using perl/Net::Telnet and expect/telnet and also perl/ssh and expect/ssh to reach the command line of the remote boxes. Scripts are working but slow.

(Yes, I do use SNMP also but many boxes do not speak SNMP)

I believe that there is some protocol or terminal negotiating that I may be ignoring that blocks when the remote box sends a query and I do not respond.

I tried to read the RFC on Telnet which appeared to have an infinite number of options. My application is very simple: get to the remote command line.

Here is an example of expect/ssh (telnet exactly the same result) that includes unexpected data then the remote blocks for 10 seconds (local or remote default timeout?) then continues with expected response.
Code:
expect: set expect_out(buffer) "admin@10.100.72.223's password:"
send: sending "xxxxx\r" to { exp4 }
(logo deleted)
  MikroTik RouterOS 3.20 (c) 1999-2009       http://www.mikrotik.com/

  ^[[?62;9;c^[[39;3Rexpect: timed out

expect: does " \r\n\r\r\n\r\r\n\r\r\n\r\r\n\r\r\n\r\r\n\r\r\n\r\n\r  MMM      MMM     
(expected data deleted)
   MikroTik RouterOS 3.20 (c) 1999-2009       http://www.mikrotik.com/\r\n\r\r\n\r
\u001b[9999B\r\u001b[9999B\u001bZ  \u001b[6n" (spawn_id exp4) match glob 
pattern " > "? no

You see I was looking for the prompt, " > ", which does appear 10 seconds later!

Part does appear to be a terminal command. I have to guess the remote box is asking me a question and I am failing to answer.

Surprising is that using ssh rather than Telnet gives the same results.
Manual use of ssh or Telnet = no delays.
Script use of ssh or Telnet = 10 second delays for each send/expect cycle!

Can some one give me a clue???
 

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set_color(1)							       fish							      set_color(1)

NAME

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set_color - set the terminal color
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   Description
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