CERN Accelerating science

This is a collection of Questions & Answers that have been treated by the Computing Helpdesk managed by the User Support group.

N.B. The number in parenthesis refers to its relative numbering in the User Support "Question-Answer" database, at URL:
http://consult.cern.ch/qa/NNN
where NNN is the problem identifier (number).

PC Support -

Question (QA 125) - 'Shortcut' list in "Start - Documents"
When I use several documents (Excel, Word, Powerpoint, etc.) in various orders, some of them do not appear afterwards in the 'shortcut' list that you get via "Start - Documents", whereas others do. In my case, all Excel documents are not listed, whereas all other Word and Powerpoint ones are. Why?

Answer - You have to verify if the setup (in your case for Excel) is correct with:

 Tools - Options - General:

Question (QA 138) - MSDN at CERN
Do I need a licence for MSDN at CERN?

Answer - MSDN (Microsoft Developer Network) is a special program for developers organised on two levels: a free level (the on-line level) available on the Microsoft Web site, and the subscription level.

The complete MSDN package consists of CDs with all the software released by Microsoft during the year (programs, operating systems and libraries). The library part of MSDN is basically a help system containing the help and sample files for all development and back office tools such as Visual Studio, SQL, Office and IIS.

The library part can be read free from the Web site as part of the free access level. The CD of the library as well as the other CDs are not free and are not distributable even if the users have their own licences.

The MSDN library, although is not directly part of Visual Studio (i.e. VB6, VC++ 6 and the rest), is essential to the use of it, since it includes the help files. It must be installed on top of Visual Studio 6 and becomes part of it.

The current situation is that in the past we have stored VB6, VC++ 6 and the MSDN library on network servers and made them available to users through the NICE menu. For VB6 and VC++ 6 this is acceptable provided the users have their own licence, since they do not get directly the CDs. For MSDN this is illegal.

However, there are now several people using this software and relying on it. Additionally, there are negotiations under way with Microsoft to have the CERN software licence include all the development tools as of the year 2000.

For new users, the MSDN library is not available from NICE so they have to buy it themselves - for example via the Software Licence Office (Marlene Prigent) - or wait until the new licence contract is in place. In any case, VB6 and VC++ 6 users can browse the MSDN library for free from the Microsoft site if they need it (http://msdn.microsoft.com/library/default.htm).

Question (QA 139) - Desktop icons
I seem to have lost all but a few of my desktop icons. Is there a way of getting them back, rather than recreating every single one again manually?

Answer - The desktop icon shortcuts reside in the directory J:\W95\Desktop. The quickest solution is to have the whole directory restored from the last good backup by an authorised person (send a mail to adsm.support@cern.ch with the details).

UNIX Support -

Question (QA 118) - Passwords on AXCAD cluster
Who can change the password on the AXCAD cluster (for a Euclid user) ?

Answer - Normally this is the same as the AFS password and it can be reset by the central Computing Helpdesk (78888). If they cannot do it (and your login or password remains invalid after the change) then it means that there is a problem with your account for EUCLID. You should report the problem to EDMS.Support@cern.ch stating that your AFS password has been changed unsuccessfully.

Question (QA 120) - Mouse usage with Exceed
I have just launched Exceed for the first time and I do not manage to get the full UNIX functionality. I have a PC with a three-button mouse, but no combination of buttons (individually or combined) are able to paste the information that I cut at other screens.

Answer - Most probably your mouse driver is not matching your mouse type. A freshly installed PC/NICE95 provides a "Standard PS/2 mouse" as driver. If yours is a Logitech (the current three-button mouse distributed through PCD), you have to associate the appropiate driver: open the "System" Control Panel (menu Start - Settings), select the "Device Manager" tab, double-click in "Mouse" to see which driver is associated to the mouse. If you have to change it double-click on this driver, then select the "Driver" tab and click on "Change Driver" to select a good one (for instance "Logitech PS/2 Port Mouse").

Question (QA 122) - Xterminals IP address
I have moved my Xterminal to another building, and in addition I wanted to change its name. I did that through the "http://network/register" Web interface, and then used the standard "boot" command to define the new IP address. However it seems that the Xterminal still "remembers" its old IP address and then does not boot from the server.

Answer - Xterminals have the ability to retain some parameters (such as the IP address) in memory even when powered off (obvioudly thanks to a battery). In order to redefine any of those parameters you have to reset the Xterminal memory first, via the command NVRAM. The documentation is quite clear regarding the steps to follow:

X Terminal Guide: section 3.4

Question (QA 124) - HOST IDENTIFICATION on HPPLUS
When I logon to Frascati using ssh from my HPPLUS account I get error messages suggesting there is a hacking problem:

 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 @       WARNING: HOST IDENTIFICATION HAS CHANGED!         @
 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
 Someone could be eavesdropping on you right now (man-in-the-middle
 attack)!
 It is also possible that the host key has just been changed.
 Please contact your system administrator.
 Add correct host key in /u1/mihai/.ssh/known_hosts to get rid of this
 message.
 Agent forwarding is disabled to avoid attacks by corrupted servers.
 X11 forwarding is disabled to avoid attacks by corrupted servers.
 Are you sure you want to continue connecting (yes/no)? 
 

Answer - The problem in this case is that HPPLUS is not the name of a real node, but a dynamic alias for a collection of 5 nodes. There is a load balancing mechanism which initially puts you onto the least loaded node, so when addressing "hpplus.cern.ch" you may actually reach hpplus01, hpplus02, etc. This confuses ssh which expects to find the same node at the same name each time.

There are several ways to get around it, but none are really satisfactory:

1. ignore the message and answer 'yes' in the knowledge that nothing "really nasty" is happening,
2. use a real hostname like hpplu02.cern.ch instead of the alias. This is ok for scp, but for ssh sessions it is not favoured by us as you would be avoiding the load balancing mechanism,
3. switch the host checking mechanism off in your local configuration file, with the command line option '-o "StrictHostKeyChecking=no"', or the '-q' option for ssh.

Note that the same error (or similar) can happen even when a user is refering to a specific node which has been reinstalled since the user last accessed it with ssh. Currently each time a machine (or node) is reinstalled, it gets a new "host key", and the users have to delete the old one from their known hosts file.
N.B. Please note that:

• there is a project in IT to work out how to store securely host keys such that they survive reinstallations, but this is not yet solved.
• ssh is not a 'deployed' service yet. There are several issues like this which must first be solved before this is the case.

Question (QA 137) - "sysname" variable setting on LINUX
There seems to be some confusion about the "sysname" setting on LINUX and the ASIS repository: "sysname" is set to "i386_linux22" but in /afs/cern.ch/asis/ there is only a i386_redhat60 sub-directory. Does it mean that we should not use /afs/cern.ch/asis/@sys in the PATH?

Answer - i386_redhat60 has been chosen for ASIS software, but Transarc (for AFS) has chosen i386_linux22 for the sysname definition. By experience the ASIS team knows that the sysname definition for AFS is not sufficient for software in ASIS. For instance many AIX 4.2 programs do not work properly on AIX 4.3 but "fs sysname" gives in both cases rs_aix42. It is why (for the time being) the @sys construct cannot be used to access ASIS software.

Another reason not to have /afs/cern.ch/asis/@sys in the path is that redhat 6.0 is not a complete architecture in AFS. So, only a few tools which were recompiled explicitly for redhat 6.0 are in /afs/cern.ch/asis/i386_redhat60. Others are in the redhat 5.1 directory.

Question (QA 141) - LD_LIBRARY_PATH on Linux
Is it necessary to set under Linux the environment variable LD_LIBRARY_PATH (as on SUN/Solaris) ?

Answer - This variable is used to determine where to search for the shared elements for dynamic loading: in Linux if you have NO LD_LIBRARY_PATH environment variable you use the contents of the file /etc/ld.so.conf (system level default).

Question (QA 146) - Colors in emacs
How can I make emacs "colourful" in order to emphasise different statements while editing code (as with xemacs) ?

Answer - By default emacs is black and white. An easy way to make emacs colourful is to add a single line to your $HOME/.emacs file as follows:

(global-font-lock-mode t)

Mail Support -

Question (QA 123) - "I'm away" message
Is there a way to influence/modify the traditional "I'm away" subject of a vacation message? Although I do not ask for it as part of my text it always appears in the automatic replies to my correspondents.

Answer - Yes; instead of providing simply the text to the "setvacation" program, you can supply:

Subject: your_subject_of_choice
  
 Text

Question (QA 131) - Search on mail folders
I have all my mail folders in AFS. How can I perform a search on the various mail folders ?

Answer - This is not yet possible with "pine" (or only with the UNIX "grep" command) but you can do it with "Netscape 4.0x" (at least on a PC): select "Search Messages" in the "Edit" menu, then follow the proposed selectors/buttons as required. This works on your INBOX as well as in the first hierarchy of stored folders (sub-folders therein have to be specifically open and searched for, otherwise an error "xxx is not a selectable mailbox" appears).

The way to search through the whole Mail Server tree is to select the "Mail on xxx.mailbox.cern.ch" folder (the top of that tree). You can do the same with local mail, etc.

Question (QA 132) - Mail Word, Excel or HTML document
How can I mail a Word, Excel or HTML document such that the recipient may read the plain text (and does not need to load Word or a Web browser)?

Answer - One possible solution, on UNIX, is to use the "lynx" line-mode Web browser to process the document before sending it. You can proceed in the following way:

lynx -dump -nolist url_to_be_translated

On a PC, Word or Excel documents can first be turned into HTML via the option "Save as HTML" in the "File" menu. Once done you could do the plain-text translation using "Netscape 2(light)" (unfortunately this nice feature was dropped in later versions): trigger the "Mail Document" option in the "File" menu, then suppress the URL line from the mail body; click the "Attach" button and select "Convert to Plain Text".

Question (QA 133) - Harrassing messages
I am getting personally e-mail-harassed by a person outside CERN; so this is not a "generic-spam" issue. What is the suggested way to proceed in order to make this known to the competent authorities and, hopefully, have legal actions following it up?

Answer - In the absence of a 'global authority' the 'standard procedure' these days is to address your complaint to the service provider who gives the 'offender' access to the Internet. In more detail, let us distinguish two scenarios. The first is an attack at your professional CERN address. In that case there is:

1. a technical action by contacting the service provider used by the offender. If you are harassed by somebody at "hotmail.com" you might try sending your complain to "abuse@hotmail.com" or "cert@hotmail.com".
2. another technical action (banning the offensive material at the CERN gateway); please contact "abuse@cern.ch" with the complete mail headers allowing to identify the origin of those attacks.
3. a "security" action in what concerns an "Internet attack"; contact "cert@cern.ch".
4. a "legal/administrative" action if the attack concerns strictly your work (e.g. somebody annoying you when putting in question professional results, therefore CERN results, etc). In that case contact the person responsible for the relations with the host states (currently G.Stassinakis) for advice.

If the attack is to your "private" address (through an external Internet provider; say you have your own hotmail account) CERN should not be involved (understandably). The technical actions still apply (transposed to your Internet provider). You might try legal actions against the offender by becoming plaintiff in front of the police or similar authorities at the offender's country of origin.

Miscellaneous

Question (QA 119) - Web Home page on nicewww
I have a problem while displaying my WWW page at http://nicewww.cern.ch/~zamora. I have set it following the instructions and I receive the following error:

    -----
    HTTP Error 404
    404 Not Found
  
    The Web server cannot find the file or script you asked for. Please
    check the URL to ensure that the path is correct.
  
    Please contact the server's administrator if this problem persists. 
    ---   
 

 http://nicewww.cern.ch/~zamora/default.htm

Answer - It's not a bug, it's a feature. You have to use

src="/~zamora/contents.htm"

src="contents.htm"

src="/~zamora/start.htm" 

src="start.htm"

This is nicewww-specific: <frame src="contents.htm"> means that contents.htm is located in the same folder as the "parent" file. And when you call http://nicewww.cern.ch/~zamora, the Web server thinks that the parent file is "~zamora", not "default.htm": it tries to retreive http://nicewww.cern.ch/contents.htm, which is missing, of course.

Question (QA 130) - Access to ROOT
I want to run ROOT here at CERN. How can I access it ?

Answer - On an AFS machine like the ATLAS_WGS set the environment variable:

ROOTSYS=/afs/cern.ch/na49/library.4/ROOT/v2.20/hp700_ux102/root

Alternative versions can be selected from the /afs/cern.ch/na49/library.4/ROOT/ directory. (See http://root.cern.ch - "Availability" - for more details.

Question (QA 145) - No "telnet" to SLAC as of September 1st 1999
When I try to "telnet" to SLAC (or use any other remote commands like rlogin, rsh, rexec, rcp) it fails. Why ?

Answer - The answer is given in the following news published by the Network team, end of August 1999:

Please note that due to computer security reasons, SLAC will be blocking
"telnet" and all remote commands (rlogin, rsh, rexec, and rcp) at their
external firewall as of
         Wednesday, September 1st

You may find additional information on this subject at:
http://www2.slac.stanford.edu/security/telnet-alert.htm
  
If this action would severely impact your work, you are requested to
contact the SLAC Security Officer (security@slac.stanford.edu) as soon as
possible.
  
Please note that secure access using SSH is possible (try "man ssh" and
the corresponding SLAC page at the URL above). You may wish to read as
well about "mxconns" at:
  
http://wwwinfo.cern.ch/dis/security/x/mxconns/
  
If you have further questions, please do not hesitate to contact the
Computing Help Desk (x78888, Helpdesk@cern.ch), and we will do our best
in trying to help you.
  
Network Operations - IT/Communications Systems