Showing posts with label ssh. Show all posts
Showing posts with label ssh. Show all posts

Thursday, May 25, 2023

Strange ssh behavior on MAC - Copy/Paste Issues


   Strange behavior of SSH on MAC, problems with copy/paste in terminal during ssh. Does the clipboard work in other applications?


   At least in "vi" the solution is very simple. Edit the file: ~/.vimrc and paste the following content:

if !has("gui_running")

   set mouse=



Monday, January 28, 2013

Installing Linux in a Sun Fire Server

The following describes the procedure for installing the operating system Debian GNU / Linux on a Sun Fire V210 Hardware. 

* As we know, this has not Hardware Out Video Card VGA or PS2 port for Keyboard. What if it has a serial port for Management.  
* This server is  64-bit SPARC architecture.


1. - Download Image.
You can download the distro from
You will need least CD number 1
Then downloaded ISO:

Please remember to burn the image a low speed, it's good to avoid some drawbacks.

2.- Place the Debian CD image to the CD / DVD ROM Server.
3. - Now, we must establish a connection via Serial COM with the Sun Fire V210 server.
We can use Hyperterminal, Minicom or even PuTTYtel.

To create the serial connection you will need the following parameters:
 9600,8, n, 1 (Default). 

The cable is a cable type used Rollover (NOT crossover). Typically console cables Cisco equipment will work.

3. - Start the server. The challenge is to make Boot from CDROM drive.
To do this, do the following: When the server is starting, we pressed Sequence 'STOP + A'.
In a conventional keyboard, this sequence is the same as 'CTRL + SHIFT + BREAK' or 'CTRL + BREAK'.
In doing so, you will get PROMPT {} Ok, when that happens we do the following:
{} Ok printenv auto-boot (To see the State Flag of the auto-boot)
{} Ok setenv auto-boot false (for setting the auto-boot Flag False)
{} Ok reset-all (Reboot the System)
4. - When the computer restarts, return to Press 'STOP + A', and at the prompt {} Ok we do isinstructed to do Boot from CDROM, so:{} Ok boot cdrom 

4.- From that moment, the server should begin to start from the CDROM drive. I recommend to use the terminal in Full Screen mode to see the installation as if it were a monitor connected to the server.

5.- From this point, it follows exactly the Debian installation procedure (Users, Partitions, Repositories, etc..)
Key Points:- Download the ISO image for SPARC 64.- The sequence 'STOP + A', which can be also 'CTRL + BRAK' or 'CTRL + SHIFT + BREAK'.- Place the screen in full screen.- If at any time the connection is lost Serial (usual with PuTTYtel), simply close and reopen theSerial Connection and type any key to recover the installation.- The system boots from the CDROM cuandl being the PROMPT {} Ok you type 'boot cdrom (Very Important ...!)
- To start the server automatically is necessary in ok prompt type the following:

auto-boot? = trueboot-device = disk

I hope it is useful.

Manual based on documentation of Professor Jose Gregorio Cotua

Friday, January 4, 2013

Cisco clear line does not work

When performing a "clear line" in a Cisco Router/Switch to disconnect a Telnet or SSH session does not work. The user still in the vty.


IMP# sh user
Line User Host (s) Idle Location
2 vty 0 idle 00:00:01 abcd aacosta
* 4 vty 2 idle 00:00:00 pepe xx.yy.zz.dd

We want to disconnect aacosta:
IMP# clear line vty 2

and still appearing:

IMP# who
Line User Host (s) Idle Location
2 vty 0 idle 00:00:39 abcd aacosta
* 4 vty 2 idle 00:00:00 pepe xx.yy.zz.dd

Procedure and solution:
There are two ways to do it:

a) Quickly and 99% sure it will works (and less likely to damage something else).
Instead of using "clear line vty" use "clear tcp line":

So (again to disconnect pepe):

IMP# clear tcp line 2

b) And the second way more drastically:

We have to search for the TCP connections in the router at that time. We use the command "show tcp brief". We filter port 23 (Telnet) or 22 (SSH) as applicable.  
For example:

IMP# show tcp brief | i \ 23 _
63820270  n.n.n.n.23        a.b.c.d.56691     ESTAB
637E1AC0  x.x.x.x.23             xx.yy.zz.dd.39431   ESTAB

The value on the left in the memory addrees within the TCB (TCP Block), this is precisely the TCP connection we will have to remove.
The command is:

IMP# clear tcp tcb 637E1AC0

NOTE: Please be sure of the value before deleting the TCP session, remember that the router may have HTTP, BGP, HTTPS and other important TCP connections.

Good luck, I hope it was useful,

A website like will provide you with the highest quality in the industry.