Posts Tagged ‘email’

Thunderbird Email Losing Sync with Google Hosted Email (via IMAP)

Monday, August 19th, 2013

Update: I wrote this too soon. This worked for a day or two, but then Thunderbird got out of sync again. I will have to try something different later.

Update 2: For a week or so, I have disabled mail.server.default.use_condstore  in Thunderbird, as suggested here: – I’m again cautiously optimistic that it’s worked around the problem.

My email is currently hosted by Google and I use a mix of the web interface (often on multiple devices), Thunderbird on a workstation, and my phone to access email. For reasons unknown to me, a couple months ago  Thunderbird client stopped updating itself when items were read or deleted from other devices or interfaces. I often resorted to closing Thunderbird, and re-opening it to force a re-synchronization.

I vaguely recall updating Thunderbird at about the same time that  this issue started, but, I’m not 100% sure. I hadn’t updated in quite a while –  probably over a year. Or, perhaps Google changed some settings on their end. I really don’t know.

I finally spent a bit of time trying to figure out a workaround or fix.

I disabled IDLE support in the email account in Thunderbird. It’s under Account Settings –> Server Settings –> Advanced. For those who don’t know, IDLE is supposed to push new email notifications to your email client, in this case, Thunderbird, more or less instantly. That’s normally a good thing.

Unfortunately, for whatever reason, disabling this seems to have fixed my Inbox’s “deleted” and “read” status issue, and I can live with a few minutes delay before my emails reach me.

Do not use xinetd to create an obscure port for SMTP

Monday, February 27th, 2012

Years ago I created a simple xinetd rule to use a custom port for SMTP.

I set this up  years ago when my local ISP started to block outbound SMTP connections on port 25 as an anti-spam measure. I had been using our web server for SMTP relay for several years before this because this same ISP had quite poor uptime in the past. When my ISP blocked port 25, my email stopped going out. I could either switch to the ISPs mail servers, or find another way to get my mail to our web server.

I can’t recall the exact reasoning, IIRC, the ISP also required that you use an email address from their domain in either the from or reply-to lines. Whatever the reasons, I created a custom port to route email through our server to continue to bypass our ISP’s email system altogether.

I chose an unused, non-standard, low TCP port and set up the redirect in xinetd. Sendmail, our SMTP server, was previously configured to  relay for specific IP addresses, I didn’t change that.

That was at least 5 years ago. It was a simpler time and spammers stuck to searching on default ports for open email relays.

Well, today I can confirm that spammers will do a port scan to find open email relays – surely there are better ways to make money that come up with crazy ways to send a bit of spam?

I learned that I had created an open relay on a non-standard port by accident. When an inbound connection is relayed by xinetd to a different port number (at least the way I did it) the service has no idea what is the real  remote IP address. Sendmail thought it was relaying for email from localhost! Argh.

Unfortunately, for a few hours today our web server was relaying spam for some Brazil IP address and advertising something or other in Portuguese. The old relay rule was turned off as soon as I traced the hole.


Does Google Apps for Domains work in China?

Tuesday, October 26th, 2010

Today I got a call from someone whom I helped setup with Google Apps for domains.  Primarily, he’s using Google to handle his email – it’s pretty much the exact same system that powers GMail, but under your own domain name.  We use it too for email.  It’s awesome.  You can use the excellent webmail interface,  and IMAP for full desktop and mobile email applications.  Plus,  it’s free if you don’t need very many user logins.

If you have a vanity domain for yourself, get Google to host your email.  You won’t find anything better, especially for $0.

Anyway, my client is in China, behind the world’s biggest firewall.  And he can’t access his email.  His web requests get  forwarded to weird places. Ironically, he sounded rather pleased, since he’s actually on vacation, but it did raise some good questions.

Does Google Apps for Domains email actually work in China?  I don’t know, it might be a weird forwarding bug.  I’m not there now, so I can’t experiment with it.  If someone reads this and can confirm success or failure with Google Apps for Domains, that would be excellent.  Unfortunately, this is some info that I can’t seem to find on the Internet.

As an aside, in  trying to figure this out, I stumbled on  Google’s Transparency Report.  It’s a fun way to see if Google services are blocked in different countries at any given time.

I wonder if any of Perceptus’ websites are blocked in China?

Bulk-Adding “To” and “BCC” Recipients to a Thunderbird Email

Thursday, September 4th, 2008

I found a new use for our Web Tools by Perceptus website.  I was sending a bulk email to friends, family, clients, and co-workers about my team’s upcoming race in the Red Bull Soapbox Derby in Vancouver.

But the list of email addresses I selected in Outlook, my PIM, would not copy and paste into a new email in Thunderbird, my email client.*  Outlook separates recipients with semi-colons, Thunderbird… doesn’t.  It’s not immediately obvious to me what Thunderbird will accept as a separator in a single “to” line. It took several Google searches (or was it trial and error?) to figure out that Thunderbird will accept line breaks, i.e. “enter”.

Now all I needed to do was find quick way to convert the list which looks like this “<Leonard>; <Me too>” from Outlook.  In this case, the extra name information that comes up in angled braces was just in the way.

Fortunately, The Email Grep Text Wizard! from our tools site,, handled the job well.  Just paste the list from Outlook and let our website return a clean simple list of email addresses.  One email per line.

* My PDA syncs to Outlook so it has to be the personal info manager, but I prefer the email features of Thunderbird.  Yes, it’s cumbersome, and no, I’m not entirely happy with the setup, but I haven’t found anything better, yet.

Reducing Memory Used by Milter-Greylist

Monday, July 21st, 2008

Our VPS was running low on free memory the last few weeks.  After a bit of research, we realized that our email greylisting software, Milter-Greylist was using the most memory of everything installed on our server.  More than our database engine, web server, email server, and everything else (not combined)!

For those who don’t know, Grey Listing delays emails in an attempt to foil spammers which don’t typically follow standards for retrying email messages. Milter-greylist is a package that works with sendmail, our SMTP server. Milter-greylist is great, however, it keeps it’s working history in memory, which was OK for the two years that we have run it.  However, the amount of spam attempts continues to rise… why don’t home users notice that their computers have become SPAM zombies anyway?

So, the milter-greylist was storing tens of thousands of records in memory.  It had to be reduced.  Rather than switch to a database driven greylisting package, we decided to start blocking some SPAM attempts earlier in the process.

We enabled the outright blocking of inbound email attempts by any IP address listed on’s SBL+XBL list.  SBL+XBL are lists of computers (built by crazy wizardry) that one can use to blacklist email attempts.  I’m uncomfortable using blacklists like this, but, what can you do?  The odds of good mail being lost are very small, and hopefully, anyone who happens to get bounced unintentionally can phone us.

So, following the simple instructions here:

We were able to reduce the traffic to Milter-Greylist and it’s memory usage by 2/3 to 3/4!  Uptime and performance of our VPS and therefore everything hosted on it should be slightly better.

Spammers suck.