October 2010 Archives

A reminder that there is a limit to the number of pages which you can print for free: the department reserves the right to charge users for printing in excess of the thresholds published on the Printing Guidelines page.

In short ...
There is a charge of 5 cents per page to you (or your supervisor or host) for all pages over a threshold which varies with your status:

• graduate students: 1,000 free pages per year


• faculty and staff: 100 free pages per year


• visitors: pages are applied to the host's quota

Spammers are constantly probing mail systems for guessable passwords and then using those mail systems to send spam to thousands of addresses. This has happened with mathmail.mcmaster.ca recently and so we have made these changes:

1. accounts with weak passwords will be locked very quickly;


2. the number of recipients will be limited for webmail.

Preventing use of our system for sending spam is very important: if too much spam originates from our network, mcmaster.ca might well end up in email blacklists and all email from McMaster to other networks would be blocked (this has happened before).

Password Scanning
We will be scanning for easily-crackable passwords more frequently and allowing only two days between emailing a warning and locking an account.

Restrictions to Bulk Mailings
You will only be able to send a message to 50 people at a time and no more than two of such messages in a five minute period.

Alternatives to Webmail
The webmail interface at mathmail.mcmaster.ca is really quite rudimentary and was never intended to be the primary interface. If you want to send out bulk email to classes, I highly recommend setting up a mail client such as Thunderbird, Evolution, OSX Mail, or Outlook Express / Windows Live Mail; we have setup instructions for our mail service.

And of course there is good old pine: the command-line interface seems awkward at first, but it's a very powerful email program.

There is no limit to the number of recipient you may specify with either pine or a mail client.

We've had quite a few abandoned print jobs of late, some of them quite large. I have turned on banner pages for the time being so that we can more easily identify the owners; wasting a small number of pages will be the cost of saving paper in the long term.

The banner pagers needed go to waste - they can go into the scrap-paper slot at the top-left bin of the rack on the wall next to the printer.

Despite a third part replacement on Monday, the printer continues to jam several times a day. And now it produces streaky output. The vendor has passed our problems on to Hewlett-Packard.

In the meantime, here's how to deal with the paper jams ...

1. remove paper as described on the panel


1. it's usually behind the the duplex unit on the left-hand side


2. open and close top of the printer




1. not the scanner bed


2. the latch is on the right-hand side as shown at right

As for the streaking, the only way to avoid that for now is to use the HH-403 printer.

The HH-303 has had major surgery and can be used again. With a brand new thingum installed, it might just be that it no longer jams repeatedly. Let me know if you have any trouble with it.

Access to mathmail.mcmaster.ca is no longer blocked from non-VPN off-campus networks.

In order to reduce the likelihood of spammers trying to use our webmail service, we are restricting the number messages which may be sent out at once. Basically, don't try to send to twenty or more people at a time (either directly or via a mailing list) using the webmail interface; use pine or an IMAP/POP client.

Access to http://mathmail.mcmaster.ca from off-campus network locations is blocked for the time being as we investigate a possible security problem.

If you connect to the campus VPN service, you will be able to use webmail. You can also use IMAP/POP clients or ssh to ms.mcmaster.ca and run pine.

Two people reported that their workstations froze with a blank, white screen. In each case, the computer wasn't frozen - only part of the display layer was; all applications were still running in the background. If this happens to you,you can unlock the screen like so ...

1. press alt-ctrl-f1


2. login


3. enter killall -9 kwin; exit


4. press alt-ctrl-f8

The problem is related to a bug in the KDE desktop environment, but I don't know what triggers it. If it happens to you more than once, I suggest you try using the Gnome desktop environment until I sort things out; you can choose an alternate desktop from the menu on the login screen.

That took longer than the planned fifteen minutes, but we are now running ms on more powerful hardware (more processors, more RAM). We will be monitoring performance.

Thanks for bearing with us.

Because the main server is struggling so under the new configuration (introduced last week), we are going to make a change this afternoon which we believe will provide immediate improvement.

The main server, ms, will be down for about fifteen minutes, during which time the workstations, email and www.math.mcmaster.ca will not work. The change will happen some time between 3:00 and 4:30.

It should not be necessary to reboot your linux workstation afterwards.

The HH-303 printer is going to be down for an hour or two. Please use the HH-403 printer for now.

We introduced some changes to the main file server last night and we're still in a shake-down period this morning. Your ms linux workstation may need to be rebooted and the systems have been sluggish. We're working on things - they should, in fact, be much better as of about 11:00 am.

The ten-minutes of downtime scheduled for 4:45 actually took 20 minutes - but everything's back up and we are able to proceed with some upgrades.

The main server, ms, and the compute server anatolius will go down for five to ten minutes at 4:45 today (Thursday). Workstations, websites, email and printing will be out of commission for that time.

Sorry for the short notice - this is a part of the longer-term server-upgrade plan which we are accelerating so outages such as the one earlier today are less likely.

... and mail was unresponsive until 2:25. It's back up now.

Authentication, printing and Windows-file-sharing (smb) services on mathserv were turned off this morning. For information on using the new server, ms, see the blog entry "Server Upgrades: Things You Need to Change".

The main server, ms, was locked up from approx. 2:00 to 2:10 this afternoon. The Web server was down for a further five minutes. Everything's OK now.

We had yet another part replaced on Tuesday, but the printer is still jamming. We're waiting to hear from the manufacturer now and will have to deal with occasional jams for the nonce.

In most cases, the jammed paper can be fixed by ...

1. pulling out the duplex unit at the left end of the printer


2. removing page wrapped around roller


3. pushing duplexer back in


4. opening and closing the top of the printer using the latch on the right-hand side near the top (not scanner; the top of the printer)

We are still waiting on a replacement part for this printer. In the meantime, it is still jamming several times each day.

In most cases, the jammed paper can be fixed by ...

1. pulling out the duplex unit at the left end of the printer


2. removing page wrapped around roller


3. pushing duplexer back in


4. opening and closing the top of the printer using the latch on the right-hand side near the top (not scanner; the top of the printer)

Webmail has been accessible on via on-campus or VPN network connections since Oct. 5th because it was used by spammers to send out thousands of spam messages. The spammers appear to have got in using some easily cracked passwords.

I will be doing two things before opening up access to webmail again:

1. asking users with easily crackable passwords to change their passwords


2. tweaking webmail so that brute-force cracking is harder to do

Webmail will probably be opened on Tuesday, Oct. 12th.

Access to http://mathmail.mcmaster.ca from off-campus network locations is blocked for the time being as we investigate a possible security problem.

If you connect to the campus VPN service, you will be able to use webmail. You can also use IMAP/POP clients or ssh to ms.mcmaster.ca and run pine.

The locking screensavers and xlock are not accepting passwords properly and so not unlocking. Until we fix the problem, you can use this workaround

1. press Alt-F1


2. login


3. enter these commands


kill-screensaver
exit



4. press Alt-F8

Access to mail and workstations will be down again from 6 to 7 Friday morning.