We've been testing Spamfilter with great success until we ran into major problems today. It seems to be related to our server running low on disk space on the C: drive, even though Spamfilter is installed on a separate drive.

The major concern is that there were processing errors for about 900 messages. The entries state that error messages were sent to message originators, but they weren't. This is a nightmare scenario where email doesn't get through and the sender isn't notified. It took us a long time to track this down and we manually generated error messages using the log file.

Here's an example log entry.

02/17/04 13:55:06:046 -- (3524) EMail from: mailto:MGuertin@crai.com" CLASS="ASPForums" TITLE="WARNING: URL created by poster. - MGuertin@crai.com to: mailto:pcabral@wgains.com" CLASS="ASPForums" TITLE="WARNING: URL created by poster. - pcabral@wgains.com   was returned to sender - server error - Requested action aborted: local error in processing (message save)

Tom,

What happened is the following. In the log, anything reported after the server error phrase is the error reported back to SpamFilter by your destination SMTP server, in this case the bolded section below:

02/17/04 13:55:06:046 -- (3524) EMail from: mailto:MGuertin@crai.com" CLASS="ASPForums" TITLE="WARNING: URL created by poster. ‘mailto:MGuertin@crai.com WARNING: URL created by poster. ’ - MGuertin@crai.com to: mailto:pcabral@wgains.com" CLASS="ASPForums" TITLE="WARNING: URL created by poster. ‘mailto:pcabral@wgains.com WARNING: URL created by poster. ’ - pcabral@wgains.com   was returned to sender - server error - Requested action aborted: local error in processing (message save)

Usually when the destination SMTP server is having problems or is down, it won't accept SpamFilter's emails at all, which causes SpamFilter to queue them for later delivery. What seems to have happened here is that your SMTP server did accept the email, but sent a disconnect code at the end that SpamFilter did not recognize, and SpamFilter interpreted it as a "mailbox not available" or "user no longer exists" error.

SpamFilter then realizes that the message was not delivered and then attempts to notify the sender with a non-delivery notice. The problem is that SpamFilter then forwards this notice to your SMTP server for delivery. If the server is still having problems then the NDR is not sent. This is probably what led to your problems.

In the latest beta SpamFilter recognizes more error codes sent by the dest. SMTP servers and tries to understand when the SMTP server is having permanent or temporary problems and tries to behave accordingly. Can you please let us know what version of SpamFilter you are using?

Roberto F.
LogSat Software

Thanks for your response.

Why would Spamfilter send the error report to the message originator through the destination SMTP server? Why not just send it directly to the originator's SMTP server, as it does with all other error messages?

Our configuration for incoming mail is:

Spamfilter=>Antivirus SMTP Server=>Exchange Server

Outgoing mail is sent directly from Exchange Server

We are using Spamfilter 1.2.0.178, Symantec NAV SMTP Gateway 3.0.0.44, and Exchange 5.5 SP4.

The only time SpamFilter actually emails the sender back is to notify them of delivery problems that occurred when forwarding the emails to the dest. smtp server. Some examples are mailbox full errors or non-existing user. Other permanent errors caused by your smtp server such as the server unavailable usually cause in the email to be queued by SpamFilter so that it can be forwarded again later when the server is back online.

When an email is rejected because it matches any of the spam rules, SpamFilter does not send an email back to the sender. Rather it outputs an error message during the incoming SMTP transactions. The remote server in turn then takes care of emailing back the sender reporting them the error.

The case you stuumbled upon was an unfortunate case were the SMTP server was indeed unavailable because of the disk full problem, but it started to accept the initial email connection from SpamFilter, making it think that the server was fine, and that the out of disk space error was similar to the "mailbox full" error. It then proceeded to send the usual Non-Delivery email to the sender bouncing it off your server, since it "thought" it was operational.

The new release will hopefully fix this problem.

Roberto F.
LogSat Software