Telnet send break fails to enter domain shell on Sun Fire[TM] system controller

Asset ID:	1-72-1010310.1
Update Date:	2008-12-28
Keywords:

Solution Type Problem Resolution Sure

Solution 1010310.1 : Telnet send break fails to enter domain shell on Sun Fire[TM] system controller

Related Items


Sun Fire 3800 Server
 Sun Fire 6800 Server
 Sun Fire 4800 Server
 Sun Fire 4810 Server

Related Categories


GCS>Sun Microsystems>Servers>Midrange Servers

PreviouslyPublishedAs
214143

Symptoms
When telnetting into a system controller it is possible that the Control + ] keystroke followed by a 'send break' at the telnet> prompt will fail to drop to the domain shell of a domain that is at the ok prompt or running Solaris [TM]. There are two common reasons for this:

The person has telnetted into the machine from which they are telnetting to the SC. A variation on this is that they have used more than one telnet session along the way to the SC. What happens is that the "closest" session catches the 'Control + ]" escape sequence and the send break command is sent to that host instead of the SC. The result is the system returning to the OS prompt or ok prompt without any apparent action having happened. Occasionally the break is captured by the remote system in between the station the person is working from and the SC, causing that system to break as if 'stop-a' had been pressed. The indicator for this is the telnet session drops and they are suddenly on their own station again.
There is another user logging into that shell on the SC (the domain shell) This is usually indicated by a "connection refused, console busy" message returned via the telnet session.

A similar situation can occur when rlogin is used to get to a machine from the person is using a tip session to access the serial port on the SC. The rlogin captures the first '~' sent and you are required to send a double tilde (~) in order to send tip commands. Example: ~# becomes ~~# as far as keystrokes. Please note that you will not see the first '~' displayed, this is your hint that it did not go through.

Resolution
The solutions to the telnet problem outlined above are varied according to cause. For the sake of clarity they will be addressed in the order presented:

There are two easy solutions to this issue:
1. Use rlogin to log into the machine from which you will contact the system controller. rlogin uses a different escape character, thus allowing the 'control + ]' sequence to work properly.
2. Use a -e option to specify a different escape key sequence on any telnet sessions short of the last one that connects to the SC. This will cause the first sessions to ignore the 'control + ]' sequence, allowing it to get to the session that addresses the SC. example: # telnet -e "^e" serengeti-sc

2. For this situation you will need to log into the platform shell on the SC and use the connections command to determine what other user is connected to the domain shell. The resolution from there is a matter more for policy than it is technical once you know who is connected.

Product
Sun Fire 6800 Server
Sun Fire 4810 Server
Sun Fire 4800 Server
Sun Fire 3800 Server

Internal Comments
Author: Don Bessee

e-mail: donald.bessee@sun.com

telnet, fail, system, controller, Control +, keystroke, domain, shell
Previously Published As
45101

Change History
Date: 2003-05-20
User Name: Administrator
Action: Migration from KMSCreator
Comment: updated by : Robin Dole
comment : No comment
date : Feb 3, 2003
updated by : James Coate
comment : No comment
date : Jan 30, 2003

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