Category Archives: Technology

Adding Envelope Sender in sendmail

Fair warning: This post is pretty darn technical and is of little interest to people who don’t muck around with Linux and/or mail servers.

Recently I had a problem with someone on a midrange.com mailing list where they sent obvious spam.

The problem was, they were a subscriber to the list and had posted before … so the normal counter measures for that didn’t work (the first post for all subscribers are held until approved, to prevent people from subscribing, posting spam, and unsubscribing).

The puzzling thing about this was … the ‘from address’ on the message was not in the subscriber list.

Turns out that Mailman will accept message based on the FROM address of the message or the SENDER address (also known as the envelope-from).  The sender addressed is set by the sending mail server and is not normally in the body of the message.

After a bit of digging around, I figured out a way to add this information to the message headers so I can more easily diagnose the problem in the future.

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Blocking Mailbait

Recently I’ve been getting a lot of mail from the feedback loops I subscribe to indicating that someone has gotten a subscription confirmation message and they considered it spam.

After digging into my logs I noticed a few things …

  • The subscription requests are being initiated from TOR exit nodes.
  • The web requests that initiate the subscription have “mailbait.info” as their referrer.

This ‘mailbait.info’ service is supposed to allow you to fill your mailbox … why anyone would want to do this is beyond me … and it has absolutely ZERO protections against submitting someone else’s email address.  As such, it just ends up generating spam.  And a lot of the twits that are using this ‘service’ are hiding behind TOR nodes, which protects their IP address.

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ReadyNAS and SMART Errors

As some of you may be aware, I don’t put a whole lot of stock in the “SMART” feature of hard drives.

Rarely have I had the SMART capabilities of a hard drive actually tell me that the drive was going to fail.

Recently I had an encounter with SMART errors in a totally different way.

Basically, my ReadyNAS NV+ storage server was telling me that “Disk 1” was having problems and might fail soon … but all my tests indicated that the drives were fine.

After a lot of hassle, and going back and forth with Netgear support, I finally figured out the problem.

It started a few weeks ago with an email the ReadyNAS sent

Reallocated sector count has increased in the last day.

Disk  1: Previous count: 671 Current count: 677

Growing SMART errors indicate a disk that may fail soon.  If the
errors continue to increase, you should be prepared to replace the
disk.

The odd thing was, the SMART information on the drives, that was available via the ReadyNAS web interface, did not indicate any of the 4 drives currently installed had any reallocated sectors.

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Spontaneous Security

Over the holiday weekend, I experienced the ultimate computer security mechanism:

“Spontaneous Security”

I was using my new Dell Latitude E6420 to do some network reconfiguration when the machine started acting weird with regard to the network.

Since this machine runs Windows 7, I decided to just reboot it to clear the network configuration.

After I restarted the machine I was asked for a password by the BIOS.

The odd thing was … I never set a BIOS password.

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I’m Shocked! It Fits!

A while ago I wrote about my iPhone Complaint … where all the accessories I was looking at were designed to fit the iPhone itself and not when it was in a case.

I was expecting to the have the same complaint about my new Motorola ATRIX … but, so far, it looks like I won’t.

I purchased a the Car Dock accessory for the ATRIX and was expecting to have to remove the phone from it’s case whenever I wanted to put it into the dock.

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Refreshing Tech Support

It’s happened again … I had some really GOOD tech support.

The phone adapter for our VOIPo service died … no dial tone, no connection, nothing.

Oddly enough, I could log in to the devices web interface … so I contacted VOIPo customer support.  After a few email exchanges, it was determined that they would need to do some interactive diagnostics to determine what was going wrong.

I called them and talked to James … he had me test a few things … and then said something truly amazing … “Could you put the VOIP adapter in to your routers DMZ so I could take a look at it directly?”.

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Android and sendmail

And you probably read in my last post … I had a problem getting mail setup my new Android phone.

I could receive mail fine … but it failed (with a totally useless message) whenever I tried to send mail.  I was sure I had the settings right (userid, password, ssl, etc).

I have my mail server configured to do authenticated sending (as all good mail server admin’s should) … but for some reason the authentication wasn’t working correctly.

I tried various setting combinations to see what might be the problem … I verified the settings with my iPhone and Thunderbird.  Everything matched up.

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And Now I’m a Droid

Android … to be specific.

I decided it was time to upgrade my phone … and switched to an Android based phone.  I got a Motorola ATRIX.

I was split between the ATRIX and the HTC Inspire … the Inspire has better battery life and a bigger screen, but the ATRIX has expandable memory and a front facing camera.

The primary reason for switching was so I could do mobile app development … I’ve got a few ideas for apps in my head and didn’t want to invest in a Mac just so I could develop them.  Android apps are developed in Java and the SDK is free (and Eclipse based).

It’s going to take a bit of time to get used to the new user interface … but so far I’m liking it a lot.

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