Contents:
General |
Mail |
News |
Web Stuff |
Printing |
Systems Security Issues
To submit your own questions and answers, send email to
the ASEL System Administrators
at sysadmin@asel.udel.edu.
Please note that the FAQ is currently under revision.
or
I would like this software package installed, who do I talk to?
Use the online Problem Report forms.
I've accidentally deleted one of my files. How can I get it back?
Use the online Problem Report form to
report to sysadmin. Make sure you also provide the following
information:
The problem: When you log into a regular POP or IMAP server (e.g. with Netscape's Mailtool), your password is sent to the server across the network in plain text; anyone who cares to can find your username and password with great ease. Your mail also crosses the network in the same fashion ... when you're physically connected to the ASEL network, this probably isn't too bad, but if you're on campus, you are likely to find some freshman in the dorms reading your mail next week.
The solution: Use our secure IMAP server, which runs normal IMAP over the SSL (Secure Sockets Layer) protocol. With this setup, everything is encrypted between your computer and the mail server. This means that your password, and your incoming mail, look like garbage to anyone who intercepts them in the middle.
Follow these steps to setup secure IMAP:
You're done.. Close all Netscape Mail windows and open up a new one.
Netscape will ask you if you want to accept the Server Certificate; this is
Netscape asking you to verify that you trust the remote server to be who it
claims to be. Our key is signed by the "Center for Applied Science and Engineering"
and the Certificate Fingerprint is "04:32:9D:22:B5:A9:7E:89:8B:60:B8:B1:16:50:E3:D6",
in case you want to check.
You probably should "Accept this certificate forever"
when Netscape asks, unless you want it to ask you again each time your read your mail.
What about Secure POP?
ASEL's mailserver will accept incoming Secure POP3 connections.
The problem is that at the moment Netscape Communicator doesn't include a
Secure POP3 client (notice that there's no Use Secure Connection
box in the Mailserver Preferences for POP). There may be a few ways of
getting around this; we'll let you know if we find one that works.
Who is ASEL blocking email from?
Sometimes, the ASEL mail system recieves large bursts of email from spammers. Often the sender's address on this mail has been forged, and the mail system spends a lot of energy trying to deliver this mail, and return it to the (non-existant) sender when it is undeliverable. Once or twice, attacks like this have literally crashed the ASEL mail server.
In order to insure the security and stability of the ASEL computer system, we have decided to block email from addresses which have sent us lots of spam. Email entering the ASEL system from these address is silently discarded - that means the sender isn't informed that his mail was undeliverable. This is because, in most cases, the return (From: ) headers on these messages are forged, which means there's noone to return an "undeliverable" message to anyways. Here's a table of the address whose email enters the ASEL BlackHole:
Please note that this blackholing isn't automatic; these people have to generate enough bad mail that the Sysadmin mailing list gets fed up. We like to think of ourselves as pretty tolerant people ... if you see an address listed which shouldn't be, please let us know. We recieve a report of all mail which is discarded, so we can track it down for you.
| Printer Name | Location | Printer Type |
| admin | Outside the Men's Room | HP LaserJet IV Si MX |
| robotics | Whitney's Lab | HP LaserJet III Si |
| color | Whitney's Lab | HP DeskJet 1600 CM/PS |
| speechdj | Across from the sound booth in the Speech Lab | HP DeskJet 890C |
admin is the default printer for Unix systems, while
robotics is for general use for the members of the Robotics lab.
How can I see what is being printed?
lpq -P[printer name]
How can I cancel a print job?
Find the job number using
lpq -P{printer name}
and then
rsh printhost lprm -P{printer name} {job number}.
How can I set up a default printer for my Unix account?
Just put the following line in your ".cshrc".
setenv PRINTER {printer name}
The printer is spitting out tons of paper when I print
a file. What did I do wrong?
You probably sent a file which the printer's postscript
interpreter did not understand. First try to
cancel the print job. If this cannot be
done, it is probably too late. Henceforth, try to use some viewer
to see your file before printing. For example, use ghostview or
pageview to see postscript files and if all is well then maybe you
can print it.
How can I print on both sides of the paper?
To print duplex, append the word "-duplex" to any printer name,
(rob-duplex, admin-duplex).
then send the print job to the resulting printer name.
How do I set up my Windows computer to use ASEL printers?
All ASEL printers are available in Network Neighborhood via the Printhost.
Here's simple instructions for how to set them up:
When Windows is done copying files and verifying license agreements, you will have finished installing the printer.
To be able to have a direct connection to the Internet over a serial modem connection PPP software is available. More information on PPP is available. You may directly use the University's PPP server, or ask SysAdmin for a PPP account here at the ASEL.
Web logs can be found in /vol/www/log; the access_log here lists all access to ASEL web pages, and the error_log reports any errors the server has encountered. If you are having trouble with your web pages, please check /vol/www/log/error_log to see if any information has been generated. You can also get the general status of the web sever at www.asel.udel.edu/server-status.
There's a nice breakdown of our web server logs at /aselonly/analog. How to read them is described here.
If you are using Windows, WWW directories are accessible via
WWW in the ASEL netgroup. The wwwdata
share is /vol/www/htdocs and the wwwlogs share
is /vol/www/log.
The server doesn't seem to follow symlinks!
The web server will follow symlinks only if the
link and the target of the link are owned by the same person.
For example, this doesn't work:
geordi[37] [~/public_html/]> ls -l x.html lrwxrwxrwx 1 lowe sysadmin 11 Dec 2 10:24 x.html -> /etc/passwd geordi[38] [~/public_html/]> ls -l /etc/passwd -rw-r--r-- 1 root bin 466 Nov 21 15:49 /etc/passwdbecause the link (x.html) is owned by lowe but the file the link points to (/etc/passwd) is owned by root.
This next one will work, though, because both are owned by the same person:
geordi[43] [~/public_html/]> ls -l x.html lrwxrwxrwx 1 lowe sysadmin 15 Dec 2 10:27 x.html -> making_cds.html geordi[44] [~/public_html/]> ls -l making_cds.html -rw-r--r-- 1 lowe sysadmin 2051 Jul 7 11:40 making_cds.html
<img src="/cgi-bin/Count.cgi?df=count.dat">
<limit GET>
order deny,allow
deny from all
allow from asel.udel.edu
</limit>
Make sure this file is readable by everyone but writable only by you with:
chmod 644 /vol/www/htdocs/secret/.htaccessThat's it!
Windows: Windows is very susceptible to viruses. The University of Delaware makes Dr. Solomon's AntiVirus software available for all computers on the University network; for information on how to set it up, see the ASEL Software Pages.
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