Spam Filter for ISPs 4.1.2.812 is a Anti Spam Software product from logsat.com, get 5 Stars SoftSea Rating, Spam Filter for ISPs is designed to be a front-end for your incoming SMTP server. It receives all emails addressed to your domain(s) and checks if the sender is listed in one or multiple DNS-based block lists; if not, the email is passed on to your main SMTP server. The administrator can configure which block lists to use, set allowed domains, filter by keyword and maintain a blacklist as well. SpamFilter runs on Windows and Linux systems, both distributions are included in the download.

Spam Filter ISP's implementation is very simple and affordable. We offer a flat-price license, regardless on the number of users. Its use is recommended for ISPs and enterprises running their SMTP server, not end-users. SPAMFilter ISP is designed to be the spam filter gateway to your incoming SMTP server.
SpamFilter ISP has been helping companies stop spam since 2002. For larger organizations or internet service providers, our SpamFilter Enterprise allows to customize even further the filtering options for each of the domains being managed.
Spam Filter ISP vs Spam Filter Enterprise feature comparison
Spam Filter ISP and SpamFilter Enterprise receive all emails addressed to your domain(s) and use several different filtering methods to detect spam in emails. Spam-free emails are then forwarded to your SMTP server(s) (see SPAM Filter's details here). End-users have web access to view their own quarantined emails. An optional anti-virus plugin is available to stop email viruses.
SpamFilter ISP's strength lies in the large number of filters that are applied to detect spam. Examples are:

* SFDB - SpamFilter's new proprietary distributed blacklist database, updated in real-time by all SpamFilter ISP installations throughout the world.
* SFDC - Our new centralized proprietary database contains hash signatures for all of the millions of emails received daily by SpamFilter installations in the world. We can thus determine in real-time if the email content hash matches spam already sent from other locations.
* Images embedded in emails are scanned for spam by Spam Filter, even if they are contained in PDFs.
* The sender's IP is listed in one or multiple DNS-based block lists.
* The Bayesian statistical analysis of the email suggests it is spam.
* The SPF (Sender Policy Framework) spam filter authenticates the sender to ensure their address is not fake.
* All of the URLs in the email are tested using the SURBL spam filter to check if they are used to host spammer's websites.
* Individual countries can be blocked by Spam Filter as wanted.
* The sender's DNS MX mail records are tested for a correct configuration.
* e-mail content is tested by the Spam Filter server against user-defined keywords (RegEx - Regular Expressions are supported by most filters).

In addition to the filter specified in other sections of the website, SpamFilter ISP supports several more filters that can be used to detect spam.
A partial list is below.
* Local IP Blacklist - Our SPAM Filter server checks if the remote server's IP address matches an entry in your local IP blacklist file, the email is rejected.
* Local Domain Blacklist - The SPAM Filter gateway checks if the domain portion in the sender's email address is in your local domain blacklist file, the email is also rejected.
* Local FROM EMail Blacklist - The sender's email address is checked against your local list of blacklisted email addresses. If present, it is rejected.
* Local TO EMail Blacklist - The recipient's email address is checked against your local list of blacklisted email addresses. If present, it is rejected.
* Attachment Blocking - SPAM Filter can check emails for specific attachments or attachment extensions. If found, the email is rejected.
* Keyword Content Filtering - Our SPAM Filtering program can check email content and subject for specific keyword and/or phrases. If found, the email is rejected.
* Honeypot Emails - You can have a list of "honeypot" email addresses. Any email sent to an address in the list will cause the sender's IP to be blacklisted.
* Connections can be rejected if the remote server does not have a reverse DNS PTR entry.
* Spam Filter is able to check if the sender's MX DNS record is valid before accepting email.
* Refuse connections if there are too many spaces in the subject line.
* Max Recipients in single session - Use this setting to limit how many RCPT TO commands can be issued in a single session.
* Max e-mail Size - Incoming emails can be blocked if they exceed a certain size.
* Reject if Empty "Mail From" - If this option is checked SPAMFilter will reject all emails with an empty "Mail From" field.
* Reject if "Mail From" = "Mail To" - Reject all emails where the sender's email is the same as the recipient's email.
* Reject if "From Domain" = "To Domain" - SPAM Filter can reject all email where the sender's domain is the same as the recipient's domain.
* Tag Spam & Deliver - Allows to tag spam by adding the header "X-SF-SPAM:Y" to email classified as spam. The email is then forwarded to the destination SMTP server. This allows administrators to handle spam as they wish on the back-end.
* Tag Spam in Subject & Deliver - Allows to tag spam by prefixing the word SPAM: in the subject line of emails classified as spam. The email is then forwarded to the destination SMTP server. This allows administrators to handle spam as they wish on the back-end. The license of this email software is Free Trial Software, the price is $600.00, you can free download and get a free trial before you buy. If you want to get a full or nolimited version of Spam Filter for ISPs, you can buy this email software.