Close SMTP Port, configure Domino

Initial attempt to close the SMTP Port and configure Lotus Domino causes not only the SPAM mails but also legitimate mails not being sent out. We have set in the router/SMTP configuration to only accept out mail for the client's Internet domain plus verify sender's domain in DNS.

Big mistake ! By accepting mail only for client's domain is alright but verifying sender's domain in DNS will not resolve properly since they are all machines within a private LAN without DNS server other than their ISP's. We have to disable that.

Meanwhile, we are reporting the "regular" spammers to their ISPs while there be actually more than just these few. Over the next few weeks, instead of diminishing attempts from these spammers, there were in fact increases by these “regulars”, all through open proxies in a revenge attempt to hit at us. They cause a heavy load on the server generating huge amounts of log entries. This is a area of weakness in Lotus Domino’s robust structure.

We kept the reports consistently sent to these open proxies owners or their ISPs closing them as fast as these spammers could get a new ones. In the end, they realize that they are fighting a losing battle and gave up.

We also have to write to the administrators of various open relay blacklists to remove our client’s IP address from their block list and it is only after they conduct a test to ensure that the problem is fixed.

Even weeks after, we still have users who could not send to a certain domain because they have an old version open relay blacklist and we have to write to them to remove our client’s server from their list.

The more we have to deal with this type of abuse from spammers, the more we dislike SPAM.

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