It appears that .NET's SmtpClient is creating emails with an extra dot in host names if the dot was to appear at the beginning of a MIME encoded line (e.g. test.com sometimes shows up as test..com). Example code:
[TestMethod]
public void TestEmailIssue()
{
var mail = new System.Net.Mail.MailMessage();
var smtpClient = new System.Net.Mail.SmtpClient();
mail.To.Add("Test@test.com");
mail.Subject = "Test";
mail.From = new System.Net.Mail.MailAddress("test@test.com");
mail.Body = "Hello this is a short test of the issue:"
+" <a href='https://test.com/'>https://test.com/</a>: ";
smtpClient.PickupDirectoryLocation = "C:\\temp\\";
smtpClient.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.SpecifiedPickupDirectory;
smtpClient.Send(mail);
}
This creates an .eml file that looks like this:
X-Sender: test@test.com
X-Receiver: Test@test.com
MIME-Version: 1.0
From: test@test.com
To: Test@test.com
Date: 6 Jul 2011 15:55:28 -0400
Subject: Test
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: quoted-printable
Hello this is a short test of the issue: https://test=
..com/'>https://test.com/:=20
When sending the file, or opening in Outlook (or any other program), the double dots show up (i.e. test..com). Note that if I remove the extra space (in "is a"), that test.com shows correctly since the dot no longer appears at the beginning of the line.
This causes a problem when trying to send website addresses, and we get calls from clients saying this they cannot click our links.
Has anyone else experienced this? How can we resolve this issue other than writing our own encoding?