System Administration

ZyXel ZyWall Glitch: Routing External Traffic to Local Interface (won't forward packet to gateway)

The symptom was that I was trying to connect to a machine with an IP address in our public address block. The router would not pass the traffic up to the gateway, or out to the switch that was the public internet. My traffic was stuck inside the router. I dug around for a long time, but found no configuration that would have caused this.

Freenet Freemail with Stunnel and Thunderbird

This is a short tipsheet, not a full tutorial. It'll help if you have freenet running on a server, and want to connect to it to interact with freemail.

Password Management and Two Factor Authentication: LastPass and Yubikey

LastPass is a password management add-on for web browsers and mobile phones. Yubikey is a 2-factor authentication device that pretends to be a usb keyboard, and types a one-time password when activated. LastPass integrates with Yubikey, protecting your password vault.

The integration is smooth, and I like it, but there's a risk if you lose the Yubikey, or it breaks. One fix is to buy two Yubikeys, and store one in a safe place.

Wireless Router as an Access Point

Access points are pretty expensive, but home routers are cheap. The paradox here is that the router does more "stuff" than an access point.

Single Antenna Operation

The Aironet 1200 has two antenna connectors, but you can use a single antenna. Just use the right antenna connector, which is labeled "primary".

Cisco 1200 Antenna Options

Cisco products have changeable antennae. Some don't even come with antennae.

Setting up your new (used) Aironet 1200, IOS style

Let's say you're the kind of person who prefers to type rather than click and wait. I'm the kind of guy who doesn't like to write tutorials that require screenshots.

Cisco Aironet 1200 Notes

I have 10 of these to sell. They are on LA Craigslist for $30 local pickup, and 0.7 bitcoin shipping included on bitcoinclassifieds. I can list on ebay for around $50 shipping included.

Distribution Group Doesn't Accept Incoming Mail from Internet, Exchange 2010

In Exchange 2010, the default settings won't allow email inbound from outside senders. This is due to a requirement that the senders be authenticated.

Migrating with Data...

It's one thing to upgrade software. It's an entirely different thing to migrate to new software. If you have a whole system of software, integrated in to a mega-app, it's even more difficult.

D-Link Switch Power Adapter Barrel Size

I had a couple of these, and lost the power adapters. (OK, someone else lost them, but whatever.) As always, the voltage and current matter, and these guys use 5V 1.2A or 2A.

Using Mutt to Read Spam and non-Spam Messages, and Train Spamassassin

This explains how to set up your server to go over email messages that have been rejected as spam, and then help train the Spamassassin Bayesian filter to correctly identify these messages.

Serve a Stream from a Webcam by Bypassing a Password with a Proxy

This is a one-line trick to serve images from a password-protected webcam to the world.

curl -i http://admin:@ | nc -lCt localhost 10203

My webcam doesn't have a password, but it could. What this does is use curl to get the stream, and then use nc to serve it to a client.

Cloud Computing Costs

I was checking out cloud services a year ago, and pricing them out. The general rule of thumb seemed to be that the up-front costs were lower, but the cost over time was higher. The ongoing costs generally work out to around $60 to $500 per application per user per year.

A typical situation is buying 25 Exchange mailboxes for $5 per month. That's $1,800 per year. That's cheaper than buying a server and Exchange, but not necessarily if you factor in other services running on your hardware.

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