Re: again problems with spam

Giganews Newsgroups
Subject: Re: again problems with spam
Posted by:  kgmccoy (kgmccoy…
Date: Thu, 11 Feb 2010

On 2/9/2010 11:28, Angdrak wrote:
> Hi, I have a program that send mails to selected customers. I upgraded it to Delphi 2007 and Indy 10, because the in previus version (Delphi 7, Indy 9) there was the problem that all mails sended was considered spam. The new version worked fine from summer until now, where only with some mail servers, again mails are considered spam.
> Wath can I do to fix this problem?

There are numerous reasons for email to be detected as spam. Look to
your email content first - you may have keywords in the subject or
message body that trigger spam filters looking for sex and drug words.

Try sending a short "hello world" message with your code (no other
words, special formatting or attachments) and see if it gets through.
This will tell you if the problem is in the message header, the message
body or attachments.

Next, are you using a blank or default SMTP MailAgent string? Some spam
filters look for Indy emails, since at one time Indy was a very popular
spam client used by a number of spammers.

Set MailAgent to something like "angdrakmail v1.23", or copy a popular
XMAILER string from an Outlook or Thunderbird message.

This might not be an issue, since I think Indy 10 does not set the
XMAILER string for you any more. Only very old versions used a default
XMAILER string that identified the mailer as Indy.

Your sending domain may also be blacklisted. Many spam filters check for
bad (blacklisted) domains and bounce all mail coming from them.

Make sure you check the various spammer blacklist web sites and make
sure your domain is not listed. There are 40 or 50 blacklist sites.

Sending mail to spam-trap addresses can get you blacklisted. A spam trap
address is a dummy mail box set up by blacklist web site owners. If a
given domain sends enough email to it, they are automatically blacklisted.

Also automatic replies that bounce messages back to a spam-trap address
can get you blacklisted as well. Some spammers set their reply-to
address to known spam trap addresses. Replying to the spam will get YOU
blacklisted. This happened to my company and it is a royal pain to get
off the blacklists.

Last, your customers may have flagged your mail as spam in their own
spam filters.

Good luck - you have a lot of work to do :-)

Kevin G. McCoy



In response to

again problems with spam posted by Angdrak on Tue, 9 Feb 2010