SUPPORT : Technotes : Anti-Relay Problems
Question:
Whenever I attempt to send mail with Mailsmith, an error window appears, and when I check the log, I see something like:
+++ An error occurred while sending mail to ¬ "smtp.bar.com". Application error code 22315 No additional information is available.
Why does this happen, and what can I do to fix it?
Answer:
In order to thwart the efforts of spammers, many system administrators are configuring their SMTP server software to check the domain of the sender, and refuse the message if the sending domain is not a known or "trusted" domain. When using a "mail drop" service such as iname.com or pobox.com, this can lead to difficulty in sending messages, even though you're a legitimate user.
Consider the following example from the Email Accounts window:
In the "Checking" settings:
POP Server Name: pop.my-isp.com User ID: joe_user
In the "Sending" settings:
SMTP Server Name: smtp.pobox.com Reply Address: joe_user@pobox.com
In this situation, Mailsmith will tell the SMTP server that the sending user is "joe_user@pop.my-isp.com". However, since "smtp.pobox.com" doesn't know anything about the "my-isp.com" domain, it refuses the attempt to send.
The server's error message is included in the log, and usually reads along the lines of:
550 <joe_user@pop.my-isp.com>... Relaying Denied
This occurs because pobox's mail server doesn't know the domain "my-isp.com", and consequently assumes that the attempt is being made by a spammer, and refuses to accept the message for delivery.
To resolve this situation within Mailsmith, set up a "Send Only" account. In the "Checking" settings, leave the POP server name and User ID blank. Given the above example, you would specify the following in the "Sending" settings:
SMTP Server Name: smtp.pobox.com Reply Address: joe_user@pobox.com
If you wish, you can make this account the default account by selecting its name and clicking the "Make Default" button; this will make it the default account through which outgoing messages are sent.
Thereafter, when you use this account to send, Mailsmith will inform the SMTP server that the message is being sent from "joe_user@pobox.com" (or whatever your actual reply address is), and the server will accept the message for delivery.
Note that the above example uses an account where the sending and receiving domains are different. However, we have even seen cases where poorly configured SMTP servers reject local users because they expect something like
joe_user@my-isp.com
but instead are receiving
joe_user@pop.my-isp.com
This is a fault in the SMTP server setup and in such cases the ISP should be made aware of the problem. However, it can be worked around in a similar manner to the above instance.