cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Announcements

28896
Views
40
Helpful
33
Replies
Highlighted
Beginner

Console port not working.

Hello!

I would like to know if there's some situation what a console port could be disabled, or something like that.
I'm trying to configure a Catalyst 2960 Series PoE-24 by the console port using the hyperterminal, but it's not working. I verified the cable and the COM port, and everything works with another switch (same model).

Does anyone knows what could possibly be happening?

1 ACCEPTED SOLUTION

Accepted Solutions
Hall of Fame Master

Console port not working.

My colleagues have focused on the usual issues that cause the console to not work - possible issues with the terminal emulator or more likely is mis match in the speed setting of the console. If you work through those possibilities and the console still does not work then I have another possibility to suggest. Perhaps someone configure the command no exec under line con 0. This would cause the console to not work. It would display messages during bootup but would not accept any commands.

Does the switch seem to boot up normally? Was it configured with an IP address that you could potentially telnet to? This would give you a way to investigate the configuration.

If my suggestion is correct and the issue is that no exec was configured then you should be able to use password recovery to bypass the existing config and this could restore normal operation for the switch.

HTH

Rick

33 REPLIES 33
VIP Expert

Console port not working.

Hi,

Can you try using a different terminal emulator like SecureCRT, Putty or Tera Term?  SecureCRT is not free.

Also, does anything show on the screen when you console to it?

HTH

Beginner

Console port not working.

Try to change the baud rate in the terminal emulator, in some cases the administrators change it for security, i had a similar case, i was trying with everyone until find the correct one

Regards

Rising star

Console port not working.

Was the switch working previously?

Could be a different BAUD rate been set, do you get random characters on the hyperterminal session or is it just blank?

Hall of Fame Master

Console port not working.

My colleagues have focused on the usual issues that cause the console to not work - possible issues with the terminal emulator or more likely is mis match in the speed setting of the console. If you work through those possibilities and the console still does not work then I have another possibility to suggest. Perhaps someone configure the command no exec under line con 0. This would cause the console to not work. It would display messages during bootup but would not accept any commands.

Does the switch seem to boot up normally? Was it configured with an IP address that you could potentially telnet to? This would give you a way to investigate the configuration.

If my suggestion is correct and the issue is that no exec was configured then you should be able to use password recovery to bypass the existing config and this could restore normal operation for the switch.

HTH

Rick

Beginner

Re: Console port not working.

I have a pretty similar case and still stuck with no commans allowed.

I removed the compact flash card. After this, I was able to send a ctrl-break and reach rommon1 > prompt. But still no commands are accepted. How to solve it?

Hall of Fame Master

Re: Console port not working.

You picked a pretty old discussion to camp onto. You might have received a bit more attention if you had started a fresh discussion. But you asked your question here and so here are some suggestions:

- when the device boots does it send output to the console? Is the output readable text or is it gibberish?

- can you verify that you have a correct console cable for the connection?

- can you check your cable and your emulator settings by using this cable and your PC to connect to some other Cisco network device?

- if you do not have another device to test with you might try with a different cable and/or a different emulator.

- a common cause of these symptoms is a mismatch in the baud rate between the device settings and the settings in your emulator. You should try setting the speed in your emulator - start at 1200 and work up through the various speeds.

- in the original discussion I suggested that the issue might be that the config had specified no exec on the console port. Since the original poster marked the issue as solved on that suggestion it suggests that this was the issue. You might try the password recovery as I suggested and see if that helps you.

 

HTH

 

Rick

Re: Console port not working.

Hello I have a 9300 Mgig that recently just stop allowing console interface. Baud/terminal and cable are all good (tested on other devices) when i connect to the problem switch its blank no gibberish, no acknowledgment at all. Help or do i just chock this to a dead switch and hope for a RMA from cisco?!?!?!

Hall of Fame Master

Re: Console port not working.

It is not clear exactly what you are experiencing. When you connect to the console port is there any output at all to your session? If you connect to the console and reboot is there any output at all to your session?

 

Symptoms like you describe might be cause by several things:

1) configured change in speed of the console port

2) configuration of "no exec" on the console port

3) hardware failure of the console port

 

To evaluate these possibilities would you post the following outputs

show run | begin line con

show line

verify when you reboot whether there is any output at all on the console session

 

HTH

 

Rick

Beginner

Re: Console port not working.

Good Evening Rick, I have read so much of your sound advice on this board. And, I hope you're able to help. I have a 2511 Terminal Server that has been acting weird. One day it will boot fine and some days I can't access it all through the console port. 

 

Today was one of those days where I could not access it through the console port, however, I was able to access everything fine through the AUX port. I was pulling my hair out trying to change the baud rate or other configurations I could change from the AUX port. I can't even get into Rommon mode. 

 

I know I shouldn't have, but I deleted the nvram. Its still giving me issues on the console port but I can still use the AUX port but I can't do anything from the AUX port since I deleted the nvram. All that comes up is gibberish from the console port but every now and again it will pop up with clear text. Any help is appreciated. 

 

Thanks,

 

Jim

Hall of Fame Master

Re: Console port not working.

Jim

 

The variability you describe is puzzling. With most of these issues with console access once it stops working it pretty much does not work until the issue (console speed, no exec, etc) are resolved. Your description of gibberish on the console sounds like a console speed mismatch to your terminal emulator. But if I am reading it correctly after a period of gibberish then the console will start to produce valid clear text messages. Is there any chance that you sometimes access it from a different PC or using a different emulator on the same PC?

 

I am not clear what you mean when you say that you deleted nvram. Are you saying that you deleted startup config? Or is it something else that you deleted?

 

If you can still access via the aux port can you post the output of show version?

 

HTH

 

Rick

Beginner

Re: Console port not working.

Thanks for getting back to me Rick. I did erase the startup config while in
the AUX port. My thinking was that if it was a no exec was the issue and I
deleted the nvram it may solve the problem on the console side.
Unfortunately, it didn't work and I can't get the sh run for you. I can
tell you there was a short window there that I was intermittently able to
get a couple commands off after I erased the nvram, and one of those
commands was sh run. Since I erased the nvram there is no more no exec
under line con 0. I was also able to get the ip address set for eth0 before
it crapped out on me again.

I'm only using one laptop to access my home lab and that is my SP 4 and use
putty. I have it set to 9600 on the emulator and I've ran through all the
baud speeds with no luck.

A while back I was messing with the baud speeds in the rommon but I changed
it back to 9600 but it seems like I've been having issues with it ever
since.

I'm still a rookie but learning from my mistakes.

Thanks for your time and assitance.

Jim
Hall of Fame Master

Re: Console port not working.

Jim

 

I understand the logic of deleting startup config in hopes of curing what might be an issue with no exec. But in this case the cure is looking at least as bad as the original problem. If you were able to set an IP address on the Ethernet are you able to access the terminal server on its Ethernet port (ping it, telnet or ssh to it)? Can you clarify what you are able to do on the aux port? Can you execute any commands? Are you able to get into enable mode?

 

HTH

 

Rick

Re: Console port not working.

Rick,

 

  I have similar issue that console does not show any output even when I reboot the device. No gibberish, just no output. It is blank. I have tried different baud rates (1200, 2400, 3600, 4800, 6000, 7200, 8400, 9600, 10800, 11200) but no luck. Is it hardware problem? Can you suggest any other solution?

Hall of Fame Master

Re: Console port not working.

Trying all of the speed rates is a good step in troubleshooting. Sorry that it was not successful. What terminal emulator are you using? For some of the emulators it is necessary to stop and restart the connection each time you change the speed. Is that perhaps the case here? 

 

Not getting any output at all when you boot the device is concerning. Have you verified the settings on your computer for the terminal emulator? Is it possible to check your settings, your emulator, and your console cable by connecting to some other Cisco device console port?

 

HTH

 

Rick

CreatePlease to create content
Content for Community-Ad
July's Community Spotlight Awards