|
|
We had a problem last weekend with Postfix not accepting email for a single domain when it was coming from outside our network, while messages from hosts on the local network were accepted and routed with no problems. Messages from outside the network were rejected with a 450 (temporary) code and the error message “Recipient address rejected: Domain not found”. The cause did end up being a DNS problem (apparently the most common kind of issue with Postfix), but not one that I would have expected (a missing host entry for the top-level domain, so example.com wouldn’t resolve even though mail.example.com did). Finding the source of the problem was complicated because of a set of several changes during a weekend maintenance window.
Continue reading (Fix) Postfix: Recipient address rejected: Domain not found
I recently needed to add monitoring of a UPS powering network equipment to a Linux server already monitoring one USB-connected UPS. Since the second UPS also uses a USB connection for monitoring apcpusd (the standard UPS management package for Linux systems) was not seeing it. This is not a fault of the software – it’s designed to work pretty much seamlessly with detection of a single UPS and does so, but autodetectin multiple battery backups would still require some level of manual configuration – at the very least, which one(s) are powering the monitoring system in case it needs to shut down? The solution is to set up udev rules to let the system recognize each attached UPS as a distinct device using the serial number of the UPS, then follow the instructions for managing multiple UPSes in the manual. Continue reading Configuring apcupsd on Linux for Multiple USB UPSes
I ran into a minor difficulty recently on a Linux desktop PC (CentOS 5.4) updated to the recently released OpenOffice.org 3.2, specifically the Go-Oo.org variant that includes some options and tweaks left out of the primary branch. OpenOffice.org 3.2 would start without difficulties, but as soon as I started to type the application would completely freeze up or hang. I only checked this in Calc and Writer, but I suspect that it applies to all of the other components as well and from what I’ve read it’s not specific to CentOS (or other RedHat-derived distributions).
After a bit of searching, I ended up at this thread: OpenOffice-3.0.1 hangs if SCIM is active. Boiled down to something for those not interested in the technical details, OpenOffice.org 3.x has problems with some configurations of SCIM, the “Smart Common Input Method platform.”
Continue reading (Fix) OpenOffice.org Hangs When I Start Typing
I occasionally get requests from clients for assistance with sending out email marketing to their existing clients. My advice in these situations is always the same: Use A Service.
Every client that I’ve dealt with that’s interested in this kind of marketing starts out planning to do it using their regular email account, but there are good reasons not to do so. The reasons for using a service break down into three key areas: creation of your content, distribution of your content, and management of your address list. Keep reading for some notes on those.
Continue reading Email Marketing – Use A Service
I’m regularly asked by customers “Which laser printer should we get?” or “What’s the cheapest good laser printer?” Here’s an initial stab at answering those questions. I’ve been pulling together some numbers on the costs to purchase & run assorted monochrome laser printers. While there’s still work to be done on tracking down some items like maintenance kit part numbers and prices, none of the outstanding information is likely to lower the Total Cost of Ownership (TCO) of a printer.
The preliminary numbers have surprised me quite a bit.
- Brother – a company I’ve always looked at as being a good choice for a home printer – is hands-down the winner on a pure cost standpoint over almost the entire range of print volumes.
- Hewlett-Packard/HP, which I knew would command a price premium, is never even within 15% of the best TCO, with toner costs in its low- to mid-range LaserJet printers more than twice most other manufacturers.
- Lexmark, another brand that I expected to be somewhat pricey, was within 15% of the best TCO only with one low-end printer under very light loads typical of household use.
- Dell, while the numbers are incomplete, looks like a very solid value for higher-volume printing or over the long term (300,000+ pages)
Read More for print volume numbers and some specific printers.
Continue reading Monochrome Laser Printer TCO/Cost – Preliminary Results
I’m currently working up an article on the total cost of ownership (TCO) for printers and choosing printers for your office, but while I work on the details (including researching costs for a variety of printers) here’s some information on the calculations involved. This is important for small to midsize offices because the variation in cost between different printer manufacturers and between low-end, midrange and high-end printers can add up to thousands of dollars a year in consumables.
Currently I’m only focusing on monochrome/black & white laser printers. The same calculations can be applied to color and multifunction/all-in-one printers as far as printing is concerned, but they don’t take into account the potential added value of the additional features (and volume of color printing will vary by office). I’m also not factoring in the cost of paper, since it’s effectively a constant – it’s unlikely that paper cost will vary based on which printer is chosen.
Continue reading Calculating Printer Costs and TCO
I had an interesting problem with a server (Windows 2003 Standard) at a small business (6 users total) the other day – a very long startup time. The server in question is a standalone domain controller/DC as well as a database/application server and file/print server. Terminal Services is installed & configured, but rarely used – mostly for access from outside the office. Database and domain services/authentication were available fairly quickly, as were console logins (via UltraVNC/uVNC) – probably 15-20 minutes to that stage, but more than an hour before terminal services/remote desktop was available.
Digging around on the console attempting to track down the source of the problems, I found multiple services listed as “Starting” – all of them malware-based, with the actual infection cleaned out. My suspicion is that these non-startable services were causing the startup of other services to be delayed, though in this case I’m not really planning on setting up a test system to verify that.
In the rest of this post I’ll give a bit more detail on the scenario, what I found, what was needed to clean it out, and a few more notes on what I suspect was happening.
Continue reading Slow Startup with Multiple ‘Starting’ Services After Malware
While unrelated to most of the content of this site, I’d like to call your attention to David McCandless’ blog Information Is Beautiful (about graphics and data visualization) and in particular to a very nice piece on What Makes Good Information Design? – in particular the key dimensions of Interestingness, Integrity, Function and Form. Obvious in some ways, but still worth considering. Read the comments as well – there’s some worthwhile discussion in there.
He also has a few items related to medical statistics, one of which I’ve passed along to customers: How Safe is the HPV vaccine? (admittedly a controversial subject, as reflected in the comments).
Ran into an interesting problem this evening – I was helping someone who was having problems with installing Office 2007 on an XP system with Office 2000 (I believe Professional) installed. The problem was that when the actual installation process started, it would hang up because another installation was running.
The standard fix for that is restarting the system to let the in-progress installation do the processing that it needs a system restart for, but in this case that wasn’t the issue.
Continue reading (Fix) “Another Installation is Already In Progress’ installing Office 2007 over Office 2000′
Earlier this week I spent some time troubleshooting a browser-based application that a client is using. The problem cropped up on a PC with a clean install of Windows XP SP3 after assorted system corruption that wasn’t worth the time to repair.
Continue reading Avoid VBScript for Web Apps
|
|
FreshBooks
PRTG Network & Traffic Monitors