Garbage on SOL console (PE1950/lenny)

[Alexander Dupuy]

Guigui wrote:
> Problem is that when I'm not connected to the SOL console,  it often
> gets garbage characters which are logged as a failed login attempt
>   

We ran into this problem on PE 1950/2950 III systems as shipped from 
Dell, with RHEL 5 installed (by us) - the problem is entirely OS 
independent, we saw it also with initial ISOLINUX and GRUB bootloaders.  
I don't have the exact subject line at hand, but if you look in the 
archives from late last year you can find my posting of the problem, and 
(I think) posting of the solution (nobody else had reported this before, 
so I had to figure it out myself, but you will benefit :-)  We had never 
had this problem with earlier PE 1950/2950 systems, will soon learn 
whether it also exists with new R710 systems.

The solution is to disable the IPMI-over-serial-port support on the BMC 
(the problem is that the login prompt from Linux - or any other output 
to the serial port - is interpreted as IPMI commands, for which an error 
is generated, which generates more output from Linux, ad infinitum).  
You can disable this using the Dell syscfg tool which is I think part of 
the Dell DTK (you don't need to install OMSA, although it might be 
included in that as well) and possibly with ipmitool (although I'm not 
entirely sure about that, and don't know the specific command), but 
often the most convenient way to deal with this, especially with 
hardware fresh from Dell, is to use the BMC configuration in the BIOS 
setup (Ctrl-E) and select reset to defaults (for whatever reason, Dell 
ships with settings different than the defaults, at least for 
IPMI-over-serial).

The specific syscfg command to use is:

syscfg serialchannelaccess --ipmioverserial=disable

Once you do this, you should no longer see garbage on your serial ports 
(is it really garbage? i.e. NUL and other weird ASCII that might 
indicate a serial speed mismatch, which in theory should not be possible 
- or is the garbage just odd ASCII error messages that are invalid 
logins? which is what I was seeing if I disabled getty and did a cat 
/dev/ttyS1).

@alex