The "max-recipients" option limits the number of recipients per message for all messages that come into your server (through spamdyke). So if your clients are using your mail server as their outbound SMTP server, this feature will limit the number of recipients on each of their outbound messages. If they are running their own mail servers or are using a different outbound SMTP server, this option will have no effect. If you're using a mailing list software that delivers its messages by making SMTP connections to a mail server (e.g. Mailman), this feature will interfere with delivery. If your mailing list software runs the "sendmail" command to deliver its messages (e.g. PHP), this option will have no effect.
Also, "the number of recipients per message" may be very different from "the number of addresses on the To: line". This is due to the way SMTP works. After a remote client connects to the server, it first takes care of any preliminaries (initial greetings, authenticating, starting encryption, etc), then it identifies the sender's address. The sender address is the address to which a bounce message will be sent and may be completely different from the "From" address that appears in the message (the "From" address is part of the message data). Next, the remote client begins sending recipient addresses. The server must accept or reject each address individually. This is where the "max-recipients" option becomes active. spamdyke will accept recipients until the maximum is reached, then it will reject the rest. If the remote client doesn't disconnect when it receives the errors, it may send the message data. This feature is primarily intended to prevent spammers from connecting to a mail server and delivering a single message to thousands of recipients in a single session. When legitimate mail servers are blocked by this feature, they will retry the rejected recipients later. For example, if a remote server tries to deliver a message to 20 recipients but the maximum is set to 5, it will (should) make 4 different connections. The first time, 5 recipients will be accepted and 15 will be rejected. The second time, 5 recipients will be accepted and 10 will be rejected, etc. (Some mail servers won't attempt to deliver to multiple recipients after the first connection where some are rejected. If that's the case, a message to 20 recipients will be delivered in 16 different connections, not 4.) However, most MUAs don't work this way. If your clients are delivering their mailings by adding thousands of addresses to Outlook's "Bcc" line, Outlook will see spamdyke's rejection code and it will stop the delivery. The user will see an error message (which they won't understand). You'll get phone calls. Authenticated clients are not blocked by the "max-recipients" filter anyway. The "filter-level" option is mostly intended to provide an easy way to require authentication before messages will be accepted, which many administrators have requested. The "allow-all" and "reject-all" values are included for completeness; I don't really think anyone will need them. I'm sure you've already tried this (and I sympathize, having tried the same thing) but the correct solution is to educate your users. They need to understand that their actions are irresponsible and they are disrupting mail services for everyone. Try pointing them towards a reputable mailing list provider (I've worked with Maestro, Blue Hornet and Exact Target in the past). If they won't stop, point to your Terms of Service which (should) prohibit this kind of activity. If they still won't stop, you can set up another mail server just for their use so your other clients won't be inconvenienced when it gets blacklisted. Or you can cancel their accounts. Good luck. -- Sam Clippinger Marcus Andree wrote: > Hello guys, > > I'm doing some consulting services for a small hosting company and > we're evaluating > the use of spamdyke with out plesk-based Linux servers. > > We host about 100 domains and spammers have been hitting us hard. > After some work > we were able to live with a spam hit of 100000+ incoming spam messages > per day, as > they were not affecting our business. Spamassassin was activated to > limit the noise. > > Now, we're migrating one of our servers to a new machine and this time > we need to > address other issue: many of our clients have internal lists of > customers e-mail addresses. > Quite a few trigger daily emails to thousands of recipients. Our email > server was listed > a couple times on a number of spamming servers lists. > > So, we need to limit the number os recipients that our clients may > send. I was looking > for some clues on max-recipients usage on this list archives and have > a few doubts: > > - it seems to be a feature aimed primarily to limit the number of > _incoming_ messages, > not _outgoing_ emails, right? > > - does it work with _authenticated_ clients that use our email server > as relay from MUA > software as Outlook and Eudora or by authenticating, users will > bypass all filters? > > - will max-recipients settings affect the mailing lists processing? > > I've read the documentation about the "filter-level" option, but it > isn't clear for me if > setting it to "normal" will have the desired effect... > > Any ideas on this? > > Thanks in advance. > > Marcus > _______________________________________________ > spamdyke-users mailing list > [email protected] > http://www.spamdyke.org/mailman/listinfo/spamdyke-users > _______________________________________________ spamdyke-users mailing list [email protected] http://www.spamdyke.org/mailman/listinfo/spamdyke-users
