Getting console access on freshly built AIX 5.2

Hi folks,

I'm unfortunately only a Solaris/Linux guy and have a problem I can't solve. As part of an assessment of some network security software, I need to perform vulnerability scans and log (syslog event) collection from an AIX box.

So I have a pSeries "B80" in front of me running AIX 5.2 and the thing boots but won't give me a serial console. I can *see* stuff such as daemons starting, etc but at the very end of the boot process I get no console. The server has no IP address configuraion, has no video card and the guys who built it (who also know very little) from the rental company don't know what to do.

With a Solaris server or Linux server the console would just work. This thing has three serial ports - two on the back and an RJ-45 on the front. The front port appears to do nothing except echo back whatever I type on it, while the others give me the "Press <blah> to make this the default console". I can interface with the various boot/diagnostic menus via the serial console at least, and I had single user mode running but I couldn't find a way to bring the console up in multi-user mode.

Seriously folks I have no idea how the foibles of AIX work. Any advice at this point is a godsend.

I don't have a B80 but here are some ideas.

It sounds like you are getting a console since you can run single user mode. However, I'll pass some of this along for reference.

Looking at page 28 in http://publib16.boulder.ibm.com/pseries/en\_US/infocenter/base/hardware_docs/pdf/380579.pdf

it appears that the ASCII console should be plugged in to S1 on the back. You should get the "Press <blah> to make this the default console". Then when the word keyboard comes on the console press the number 1 key on the keyboard to display the SMS menu. Within those menus there is a selection for setting the console. However I think that is set when you press the 1 key.

When you boot to single user mode use "smitty console" to set your console. Also make sure that /etc/inittab has a line that reads something like

cons:0123456789:respawn:/usr/sbin/getty /dev/console

I suspect your nul modem cable is not wired correctly for the RS6000.

They seem to use a unique cable.

Your problem is typical of a bad cable.

During the boot sequence and also during an AIX install the console uses one type of handshaking. During AIX runtime it uses another!

All good fun.

Check your pinout, it should be:
2 to 3
3 to 2
7 to 8
8 to 7
4 to (6 and 1)
(6 and 1) to 4
5 to 5

You also have to consider the terminal settings, what terminal are you using?
What speed, duplex, data and stop bits, handshaking, etc.

Typically, for say a windows hyperterminal session, you would use 9600, 8, n, 1, hardware flow control.

9600 and 8N1 was correct for all the classical R/6000 machines. At some point this was changed to 19200, 8N1. The p6xx and the p5xx are definitely using 19200, the B50 has used 9600. Which speed the B80 uses i don't know but it can only be one of these two.

The pinout is a simple Nullmodem cable (serial RS232, but RX/TX crossed out) but you usually need a gender changer (depending on the cable, there are some with the right connector) because of the "wrong" DB25 connector IBM uses.

If you are asked to press function keys use the following schema: <F1>=<ESC><1>, <F2>=<ESC><2>, etc.. <F10>=<ESC><0>

bakunin

19,200 came in at power5, so the b80 default is 9,600 but beware this can be changed on all machines when AIX is running and on power 5, and later, when either the boot menus or AIX are active.

The b80 has 9 pin serial ports as do all later machines.

It sounds like perhaps the inittab file is not enabling logins from the console.
I'll give that a shot, but embarrassingly I set the root password in single user mode and...ah...forgot what I typed (sometimes bad behavior creeps in to the lab...)

Anyway if I can't remember it (I seem to only get one chance to type it before it kicks me off forever), I shall have a look at the inittab file. Other than that, we have an AIX engineer coming in to perform any work required on Monday (including full reubuilds if required).

If I can remember to be a good netizen I'll even post back here with the confirmed solution and what the core issue was.

Posting what the solution was once you discovered it will be greatly appreciated. I'd like to THANK YOU in advance for this consideration.

There is a thread in the FAQ dealing with how to get into an AIX machine without knowing the root password: Lost root password / Can't login as root

I hope this helps.

bakunin

FYI.

I have a B80 that I configure last month. I used the front panel TCP/IP connection (upper-right) to connect to my old 3150 console, not a card slot on the back. There's some conversion of TCP/IP-cable to 3150-cable that I used.

Regards

AIX has login via the serial console disabled as a default. So you need both a suitable serial cable and to change some AIX settings. If you don't have an original IBM serial cable you might use a blue laplink one. Access the B80 with a VT100 Term configured at 9600-8-N-1. Start server, choose the right console by pressing the number that is displayed on your screen and then get into maintenance mode by pressing "5" after the word "keyboard" appears on the screen (if you don't see anything you got the wrong cable or chose the wrong console before). Then access a rootvg, start a shell and mount rootvg (writing from memory but these steps are being offerd by menu). When you got the root shell export TERM=vt100. Open SMIT, choose devices and then the TTY in question. Change the following parameters:
* enable LOGIN - enable (switch)
* STTY attributes for RUN time - clocal (add)
* STTY attributes for LOGIN - clocal (add)
* Apply changes to Database only - yes (set)
Exit smit and reboot. The server should come up and let you log in via the console.

One more hint: This description applies to the older workstation and standalone server Power technology. Steps for LPAR capable servers are slightly different as not every serial port of those machines may be used for login into the OS. Secondly baud rate of newer servers is higher.