Servers and Networking

Resources for learning SQL

Dave Farquhar Servers and Networking , , ,

Whether you’re a sysadmin, an analyst, or use a computer for something else professionally–even if you’re not a database administrator or developer–SQL is a useful skill to know. I’ve gotten by for 20 years without knowing much more SQL other than simple SELECT statements, but those days are rapidly winding down–if I want to be good at my current job, I’m going to have to take some time to learn SQL. If you’re in the same boat, here are some resources for learning SQL.

Here are two resources:

http://pgexercises.com/

https://sqlschool.modeanalytics.com/the-basics/introduction/

SQL is the underlying language behind Oracle, Microsoft SQL, MySQL, PostgresSQL, and probably a few other databases I’m forgetting. If you’re doing something beyond Microsoft Access, it’s probably using some kind of SQL. Each implementation has its own quirks but the basics remain the same between all of them.

Why you can’t get to Google and Facebook on AT&T U-Verse

Dave Farquhar Servers and Networking ,

If you have AT&T U-Verse, from time to time you may have issues with Facebook or Google sites like Youtube not working, while the rest of the Internet works fine.

The solution is simple but non-obvious: Disable IPv6.

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How to use a router as a switch

Dave Farquhar Servers and Networking , ,
How to use a router as a switch

Most of us have an old router like a Linksys WRT54G laying around, or if we don’t, it’s very easy to find one–the nearest garage sale or thrift store is a good bet–but sometimes all we need is a switch, to hook up a couple more computers or other devices to a wired connection. Using a router as a switch wastes some of its capabilities, but it’s easy to do. Here’s how to use a router as a switch.

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What to do when your router isn’t in the DD-WRT router database

Dave Farquhar DD-WRT, Servers and Networking , , ,

If you have a router and want to run DD-WRT on it, but can’t find the router in the router database, you may have learned the hard way that the router database is a couple of years out of date.

But not all hope is lost. Here’s how to find a build, if one exists.

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The difference between the TP-Link TL-WR841N and TL-WR841ND

Dave Farquhar Servers and Networking , ,
The difference between the TP-Link TL-WR841N and TL-WR841ND

I see people asking about the difference between the TP-Link TL-WR841N and TL-WR841ND (sometimes they just ask TP-Link TL-WR841N vs TL-WR841ND). Since nobody else seems to have answered, I’ll take the question.

TP-Link TL-WR841n
This is the TP-Link TL-WR841n.

Here’s how to decode TP-Link model numbers. This is true of the 841 series, which is my go-to for the moment when I need a capable yet inexpensive router, but also other TP-Link models.

“TL” stands for TP-Link. “WR” stands for wireless router. The numbers tell you where the model stands in the product line. Beefier routers have larger numbers. “N” stands for the type of networking, which, in this case, is 802.11N. “D” stands for detachable antennae.

If you don’t need to be able to detach the antennae to replace them with bigger, longer-range models, you can save some money by buying the N-model. Otherwise, the TL-WR841N and TL-WR841ND are functionally identical. They both use the same DD-WRT build.

How to size your Internet connection

Dave Farquhar ISPs, Servers and Networking , , ,

So I understand ISPs are upselling connection speeds saying it’ll make Netflix work better. That’s a nice theory. But if you’re already over 10 megabits, there’s a decent chance your connection speed won’t do much for Netflix at all. Here’s how to size your Internet connection. Read more

Keeping your NAS off Google

Dave Farquhar security, Servers and Networking ,

I read in a couple of places the last few days about search engines picking up data stored on poorly configured consumer routers acting as a NAS. This isn’t a case of being evil; rather it’s a case of people accidentally posting stuff in public where search engines will find it. Finding difficult-to-find data is what search engines do for a living, so I don’t fault any of the search engine companies for this. Keeping your NAS off Google is probably something you want. Here’s how to do it.

The solution is to know what you’re doing when you need to access your data both at home and on the road. I apologize for the snark, but there are consumer-friendly ways to do it, like using a cloud provider.

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Keep cordless phones from interfering with Wi-Fi

Dave Farquhar Servers and Networking , , ,
Keep cordless phones from interfering with Wi-Fi

Long ago, when dinosaurs roamed the earth and knights in shining armor fought them, people had landlines. And they plugged cordless phones into them. Everything was great. Then phones started using the 2.4 GHz and 5 GHz frequencies. Wi-Fi came out using the same frequencies and the two interfered with each other. Now, it seems increasingly difficult to keep cordless phones from interfering with Wi-Fi.

Many people have neatly solved the problem by using cell phones exclusively. But what if that isn’t an option? You’re actually in luck, and you don’t have to dig up a 20-year-old 900 MHz phone and try to find a battery that works in it.

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How to find inexpensive routers to run DD-WRT

Dave Farquhar DD-WRT, Servers and Networking , , , , , ,
How to find inexpensive routers to run DD-WRT

I’ve been using and recommending DD-WRT for years, but it’s getting harder to find inexpensive routers to run DD-WRT. Many inexpensive routers now use non-Broadcom chipsets that DD-WRT and other third-party firmware don’t support well, or at all.

But there’s still a way to get inexpensive, compatible routers that isn’t likely to change any time soon.

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Build the best, most secure wifi in your neighborhood

Dave Farquhar DD-WRT, Servers and Networking , , , , , , , , , , , , ,

My neighbor asked me for advice on setting up wi-fi in his new house. I realized it’s been a while since I’ve written about wi-fi, and it’s never been cheaper or easier to blanket your house and yard with a good signal.

Blanketing your house and yard while remaining secure, though, is still important.

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