CSL: General FAQ

This page attempts to answer some common questions about the CS Lab. Please contact the Lab Staff if you have any comments, corrections, or suggestions.
General problems & questions

For general problem reports please contact the Lab Staff. Please included detailed information on your problem, the more detailed, the better. Upon the receipt of the problem report, our automated problem queue will generate a unique problem ID and include this on the e-mail Subject line. The line will look similar to this:

Subject: Re: [Duke CS Request #20788] Can't send e-mail 

Please make sure to keep this Subject: line in all follow-up messages concerning that specific problem.

If you have a question about how to set up your environment, how to use a program, how to etc..., please do not send this to problem. In these cases, please ask a colleague, or send a message to the duke.cs.questions newsgroup. This newsgroup has an e-mail-posting interface which can be accessed by sending e-mail to csquestions@cs.duke.edu. To subscribe to the questions e-mail list, use the command:

	echo "subscribe questions" | mail majordomo
Opening/closing of CS accounts

CS accounts are separate from accounts provided by Duke OIT, and are generally restricted to faculty, students and staff having some close department affiliation. Accounts will be made available to qualifying persons, or may be requested by contacting the Computer Science Lab Staff. More information about account availabilty and policies can be found in the Lab Accounts section of the web site.

Account closing are handled in a detailed, semi-automated manner; this is necessitated by the large number of undergraduate accounts in the department. Users receiving account closing notices should not panic, these notices are sent well in advance of any actual account closing, and are intended to provoke a response from the account users. For more detailed information, please see the account closing policy page.

Changing your password

To change your password, run the folowing command at the UNIX/Linux command-line prompt:

	passwd

You will be prompted for your current password, and then for your new password (you'll have to type the new one twice). If your new password isn't sufficiently obscure, it will be rejected.

Forgot your password?

If you have forgotten your password, please contact the Lab Staff. If you have just changed your password and have forgotten the new password, we usually can reset your password to the previous value. In all other cases we must reset your password to a new value. We are unable to tell you your password; they are stored in an encrypted form.

Note: we do not give out passwords over e-mail! We have no way of verifying user's identify over e-mail and it is insecure to have passwords stored in text messages. If you are not able to physically come by a lab staff member's office, please contact a faculty member of administrative staff by phone and we will relay your reset password through that person.

Checking group membership

You can check your group membership by using the UNIX/Linux groups command. Note that when you are added to a new group, you may need to login again for the new group membership to take effect.

You can check the membership of a particular group by using the getent command; for example to find the users belonging to the group compsci330, you would use the following command:

	% getent group compsci330.sp
	compsci330.sp*:6123:fred,jones
	% getent group | grep compsci330 
	compsci330.fa:*:6080:john,smith
	compsci330.sp:*:6123:fred,jones

where users fred and jones are the only members of this group. Note that this will not include group members who have the group ID as their primary group number in their passwrod entry

Group access to files

Department members make frequent use of UNIX groups to share files among group members. It is possible to set up shared directories such that all files created within the directory inherit the default group, (see the discussion about the group ID bit in the chmod man page), but it is up to the individual users to make sure the files have the proper permissions. This can either be handled manually, using the chmod command, as shown below:

% chmod g+w newfile

Alternatively, the user can affect all file creation permissions by changing their umask to 002 (the default is typically 022. Note if this method is chosen, this will affect all files created by the user!

Remote logins/Can't login to my desktop machine

If you are having trouble connecting to a department machine via ssh, please try connecting to login.cs.duke.edu first. Access to individual desktops is not guaranteed; these machines might be down for repairs or even be replaced entirely!

If you are experiencing problems logging into a known-available machine, particularly with the newer, Linux-based machines, you may have a problem with you account configuration files, or dot-files. Please see the Linux FAQ for more information.

Disk space and quotas

The Computer Science Lab provides ample disk space and quotas to store information for courses and research. We realize that at times users need more space for temporary storage. In events where short term space is needed, please use the directory /usr/xtmp/. Any files in this directory that have not been accessed in thirty days are purged automatically; please make sure to move any desired files to somewhere more permanent before they expire.

If you need space for a research project, please contact the principal investigators of the project about the possibility of acquiring project space; there might be a project disk available for this purpose.

A more complete description of disk space options can be found in the Computer Science Lab Disk Usage Policy.

Information about managing your disk quota can be found in the document Understanding and Monitoring Your Disk Quota.

Restoring files

To have lost files restored from tape backups, please fill out the File Restore form, and your request will be sent to the Lab Staff problem queue.

As of March 2004, all user and many project filesystems have been moved to a Network Appliance storage appliance. This device provides a snapshot feature which in most cases should allow users to recover lost and deleted files on their own. The snapshots on the file systems will allow you to restore files that were changed or deleted for several hours, days, or even a week ago. To learn more about this feature, please take a look at the Snapshot FAQ.

Personal Computers in CS

Users are permitted to bring in their own computers, and request access to a special-purpose network within the department. Requests to have a computer connected should be made to the Lab Staff and should include your room number and the number of the port you would like to use. The ports are designated by a letter-digit combination, such as B11 or C3. Users should never disconnect department computers from the network, unless so directed by the Lab Staff!

Wireless Network Access

Wireless access within the department is now provided by Duke OIT. For information on managing personal wireless access, or about visitor-access to wireless, please see their wireless access page.

E-mail security issues

Users may occasionally receive e-mails of a suspicious nature, either asking the user for account information (such as passwords) or containing attachments which the user is instructed to open. These e-mails are invariably bogus and the user should ignore these requests. The CS Lab staff will never ask you to provide your password in an e-mail. Additional information about requests for account information (generally referred to as phishing) and suspicious attachments which may contain viruses is available. Users may attempt to alleviate such e-mails, as well as unsolicited SPAM by taking measures to prevent their e-mail addresses from being harvested from department or other web sites.

Dealing with spam

The department has implemented a spam e-mail solution that enables individuals to decide if they want spam filtering turned on or off, and to specify what level of filtering they would like. This solution works with all the most popular e-mail clients and has been very successful in cutting down the amount of spam the department receives. As with any spam filtering system, this system may occasionally produce false positives. For this reason it is recommended to send tagged spam to a separate folder which can be cleared out occasionally. Please see the advanced guide or contact the Lab staff if you think legitimate e-mail is being tagged as spam.

Reading E-mail seems slow

Although a multitude of reasons can contribute to slow e-mail access, in particular the lab staff has found that excessively large "inbox"-es are a common cause of this complaint. The CS Lab does not restrict "inbox" size, so that users will never lose e-mail due to a quota issue. However, users are encouraged to intelligently manage their "inboxes", both to provide faster access for themselves as well as to lessen their impact on a shared department resource.

Can't receive e-mail from a remote user

On occasion users have reported problems receiving e-mail from users at remote locations. Usually this is due to the sender's mail server not being listed in reverse DNS lookups. This restriction is an anti-spam measure, and most legitimate mail servers should be properly listed. If you experience this problem, please contact the Lab Staff.

Forwarding e-mail

Some users may wish to forward e-mail sent to their department account to other accounts. The department e-mail system provides flexible solutions that can be easily modified by the user.

Users who do forward e-mail to gmail (or other) accounts are strongly encouraged to filter spam before forwarding; failure to do so causes the department server to be tagged in anti-spam databases and causes forwarded messages to be delayed or rejected.

Autoresponding to e-mails while on vacation

Users who will be away from the department and wish to set up an automatic e-mail response can learn how to do so by reading our e-mail Vacation FAQ.

Mailing Lists

The Computer Science Lab runs its own e-mail server, and thus has the capability to create global e-mail aliases and mailing lists. Users can request that lists be created for various research projects and collaborations; the maintenance of such lists are then given over to the user. Addresses for these lists have the form list-name@cs.duke.edu. Any files There are two options for these lists the user can choose:

  1. a text file, owned and maintained by the user, containing a list of e-mails. These are typically stored in the global directory /home/global/EmailLists. This solution is best when the list membership is fairly static and the list maintainer is willing to perform all list maintenance.
  2. a Majordomo mailing list, which has many features, such as allowing users to subsribe/unsubscribe on their own, creating moderated lists, and archiving of files which users can retrieve. Majordomo lists are also maintained by the user through an e-mail interface. Please see the Majordomo User's FAQ and the Administrator's FAQ for more information.

Additionally, Duke OIT provides campus users with the Sympa mailing list manager: a full-featured e-mail list manager with a web interface. Addresses for these lists have the form list-name@duke.edu.

Please contact the Lab Staff if you require a mailing list to be set up.

Remote access

Users are required to provide for their own ISP's. Duke OIT does provide a list of options available to students, staff and faculty members on their remote access page.

You CS account can be accessed a number of ways from off-site. Information on web access to e-mail and shell access via a standard web-browser can be found in the Web-based Remote Access FAQ. Terminal access is also avaibable via ssh clients. Users can mount CS filesystems on their home machines, from both Windows and Mac OSX using SAMBA and ssh tunnels.

For general-purpose remote access (as opposed to intensive research computing) we recommend using the login servers (login.cs.duke.edu). Individual desktop machines are not guaranteed to be available, and storing files on these can result in data loss. Please see the Disk Usage FAQ for more information.

Web-based E-mail

The CS Lab runs web-based e-mail reader (Webmail), which can be access at https://www.cs.duke.edu/webmail

Remote e-mail access

Users are encouraged to use IMAP (Internet Message Access Protocol) for accessing their department e-mail remotely. Instructions for setting up many different e-mail clients are provided.

Remote dial-up access

As of January 30, 2004, the department no longer supports remote dial-up access. Please see the Duke OIT remote access page for more information about off-campus options. Additional remote access options for faculty are also provided by the lab.

General Linux/Unix questions

The Unix/Linux specific questions previously located in this FAQ have been moved to the General Linux/Unix FAQ.