Chris May

At Walsh Construction, we have a service that filters out our spam.  This company is called mxlogic. 

They really do a good job in my opinion.  Since we switched over to using them, I am no longer worried about giving out my email address b/c I know that spam will most likely not reach my inbox.

Now, it looks like Microsoft is going to offer a similar service:  http://www.microsoft.com/exchange/services/buy.mspx

I might want to look into this for some of my long lost email addresses.

I recently started getting some soft bounces coming back from Yahoo. 

I believe that this is a "greylisting" operation on their part:  "Message delivery has been delayed."

The typical "lists" are Blacklists (all email is rejected) and Whitelists (all email is accepted).

Greylists utilize what is called a soft error, or soft bounce on the email server. 

When sending an email, there are some errors that cause the transmission to fail and halt, and there are others that indicate that the sender should "try again later."

For example, if you try to send an email to an account that doesn't exist, the sending server will not try to deliver the message again.  But if the error is something like "Mailbox is full", then the sender will keep trying N number of times.

Almost all spammers will not bother to resend these soft bounces.  They are kicking of millions of emails, it isn't worth their time to deal with these soft bounces.

So greylisting does the soft bounce, and sees if the sender tries again.  If they do, then yahoo labels them as an OK sender, and allows their email through.  If they don't try again, yahoo can label them a spammer, and block them out.

 

I recently went through the painful process of updating all our codebase to remove all warning messages after our "successful" convesion from .net 1.1 to 2.0.

After I made all the adjustments to remove all warnings, all seemd to be well.  In fact, it was going to well, as this morning I relized that I hadn't seen an exception report come through my email in a week.

Sure enough, I went into the database where I log everything and found exceptions that were not being emailed to our development team.

The exceptions that were being thrown when we tried to email were stuff like this:

Email address problems

Error sending Error Report: Message: The specified string is not in the form required for an e-mail address.
Stack:   at System.Net.Mime.MailBnfHelper.ReadMailAddress(String data, Int32& offset, String& displayName)
   at System.Net.Mime.MailBnfHelper.ReadMailAddress(String data, Int32& offset)
   at System.Net.Mail.MailAddressCollection.ParseValue(String addresses)
   at System.Net.Mail.MailAddressCollection.Add(String addresses)
   at System.Net.Mail.Message..ctor(String from, String to)
   at System.Net.Mail.MailMessage..ctor(String from, String to)
   at System.Net.Mail.MailMessage..ctor(String from, String to, String subject, String body)
   at Walshgroup.Logging.ApplicationAudit.EmailErrorToDevelopmentTeam(String sErrorMessage, Int32 iLoginID) in x.vb:line 586 on machine y

Subject problems

Error sending Error Report: Message: The specified string is not in the form required for a subject.
Stack:   at System.Net.Mail.Message.set_Subject(String value)
   at System.Net.Mail.MailMessage..ctor(String from, String to, String subject, String body)
   at Walshgroup.Logging.ApplicationAudit.EmailErrorToDevelopmentTeam(String sErrorMessage, Int32 iLoginID) in C:\x.vb:line 586 on machine y

It turns out that we were doing 2 things that System.Web.Mail seemed to accept, but System.Net.Mail did not.

Email Address: We were using the MS Outlook way of email concatenation (using a semicolon) to send an email to multiple people (e.g. bill@asdf.com;jack@asdf.com;pete@asdf.com).  Once I changed it to use commas, everything worked, but we still had errors related to the subject line.

What we were doing for the subject line was simply to take the first 50 characters of the email error message.  In this case, this included some CRLF.  Once those were removed the email sent w/o a problem.

For more info on these classes check out http://www.systemwebmail.com/ and http://www.systemnetmail.com/.

This article shows how to create a control that will convert your email addresses into a unique code that is reconverted by javascript when the page loads... so it can't be screen scraped.

This page allows you to test you SMTP to see if it is allowing Open Relay.

Pretty cool.

I fricking hate spam...