Spam Filtering

Interpole SpamCan gives you the power to monitor and filter e-mail traffic to protect your organisation from virus attacks, spam mails and wasted bandwidth right at the Internet level. SpamCan provides for virus-free and spam-free mail. All the unwanted emails (containing spam and virus) are filtered on our Internet server before they reach your mail server and the intended recipients.

Salient Features of Interpole SpamCan

  • Triple-level Virus Scanning
  • Multi-layered Anti-Spam capabilities stops 90-95% of Spam
  • Spam Analysis Engine with auto-updates and auto-learning
  • Personal Whitelists and Blacklists allow/block emails from specific IDs/domains
  • Real-time Blackhole Lists capture data from global spam servers to block spam
  • Content filtering
  • Reports on email trends, viruses detected, spam volumes, policy violations

Email spam and virus are major problems, hence there is a great challenge to eliminate these twin threats. SpamCan provides the enterprise with excellent spam and virus filtering from an enterprise approach. In doing so, end-user productivity is increased and improved. Most importantly, security vulnerabilities can be identified, reduced and eliminated before email arrives at the corporate email servers.

How Spamcan works?

The primary advantage of this service is that email is examined thoroughly at the Internet level before sending it to the internal email server, hence minimising the impact of spam and viruses on the end user.

SpamCan :
  • Scans all e-mail passing through it for viruses through three different anti- virus software to ensure maximum protection
  • Attachments containing viruses or other security problems are removed
  • All safe content is delivered untouched

While this service will remove the vast majority of known email viruses, viruses can also infect computers in other ways. For maximum protection, we therefore recommend that you also run anti-virus software on each of your computers.

While no service or software can guarantee that 100% of all viruses will be caught, SpamCan offers an additional strong level of virus protection with its triple-level scanning.

SpamCan Features Explained

Multi-layered Anti-Spam capabilities stops 90-95% of Spam
Triple-Level Virus Scanning
  • Completely different set of actions can be applied to spam scoring above a "High Score" threshold value.
  • Spam can be tagged, rejected, discarded, archived or forwarded to other addresses for inspection by administrators

With the initial, default settings, our Anti-Spam service will "out of the box" block 90-95% of all Spam. Most of the remaining Spam will actually be bypassing our service due to tricks that spammers use. The Bayesian database support in SpamCan tries to identify Spam by looking at what are called tokens; short phrases that are commonly found in Spam or ham. (Ham is e-mail that is not Spam.) Each token is given a small score; together these scores rate the email as Spam if above administrator defined levels.

Spam Analysis Engine with auto-updates and auto-learning

The SpamCan Spam Analysis is automatically updated several times in a day with feedback from global servers. In addition, it can be trained by users who can provide it with examples of spam mail. Users can train newer variants of Spam by simply clicking on a link provided at the end of each email message.
An important feature of SpamCan is that you can create a personal "Whitelist" to ensure that your important clients and other contacts will never be blocked, even if their mail system somehow ends up blacklisted.
You can Whitelist by IP address, email address and/or content. Since SpamCan depends partially on other organisation's " blacklists", we maintain a "Global Whitelist" for all customers, and will consider your suggestions.

The primary entries in our global Whitelist consist of :
  • Major legitimate newsletters and mailing lists
  • Legitimate companies in countries that are otherwise blocked
Personal Whitelists and Blacklists allow/block emails from specific IDs/domains

You can also create a personal "blacklist" to block email from certain sources. It does not need be Spam; it can be used to block someone who is harassing your employees. Or you might want to block recruiters who are trying to steal your employees.

  • You can blacklist by IP address, email address and/or content. For example, if is harassing you, all emails from him can be completely blocked. Such blocked emails can be re-routed to your “Spam" mailbox or completely blocked
Real-time Blackhole Lists capture data from global spam servers to block spam
  • Several organizations and companies are constantly identifying the mail servers, which are actively sending Spam. They create "real-time blacklists" (RBL) of the IP addresses of these mail servers, which are updated daily, even hourly. We have chosen four of the better known RBLs for selection within the SpamCan service. (By default, all are selected.) Our main criteria was to choose RBLs which are least likely to block legitimate email.
  • A good blacklist not only quickly adds a new Spam source, but also removes it when it is no longer sending Spam. Spam is often sent through "open relays", which are legitimate mail servers, which have been (trivially) "hacked" by spammers. Typically, the owner of the mail server learns of this within a day and then fixes the problem. Therefore, mail systems should not be blacklisted any longer than necessary.
Content filtering
  • Allows/denies attachments based on filename, providing implementation of any email security policy. Easily used to block attachments which are common ways of disguising viruses, e.g. ReadMe.doc.exe These can be varied for different users
  • HTML-based Attacks
  • Scans for common signs of attack such as "IFrame" and "Object Codebase=..." HTML tags. Both have been used many times to exploit vulnerabilities in Outlook (& Express) and Internet Explorer
  • Dangerous HTML content can be stripped. Checks and traps added for all known Outlook, Outlook Express, Internet Explorer and Eudora security vulnerabilities.

SpamCan Reliability

SpamCan reduces the chance that you miss any email. This service uses two "relays" which will spool (i.e. "save") your email messages in the event your mail server is off-line due to power failure, system email crash, routine maintenance, or any other reason. When your mail server is back online, it will automatically receive the spooled email. (Our service will spool your mail for up to five days.)

Email filtering is a process of monitoring incoming email and then taking the appropriate action to protect against Spam and viruses. Certain criteria are set to determine if an email is actually Spam. Each criteria has a certain weight or score. It also uses text analysis and several internet-based real-time blacklists.

Tests and rules are executed on mail headers to determine and tag an email with Spam.
Blocked Spam messages are logged into a database. For viruses, email messages and attachments are scanned and detected to delete and/or disinfect malicious programs.

SpamCan Technical Description

SpamCan uses the following mechanisms to detect spam

Header analysis

Spammers use a number of tricks to mask their identities, fool you into thinking they've sent a valid mail, or fool you into thinking you must have subscribed at some stage. SpamCan tries to spot these.

Text analysis

Spam mails often have a characteristic style, and some characteristic disclaimers and CYA text. NESS can identify these tactics.


SpamCan supports many useful existing blacklists, such as mail-, and many, many others.


RPTN is a collaborative tracking and training database, which works by taking a signature of Spam messages. Since Spam typically operates by sending an nearly identical message to hundreds of people, RPTN short-circuits this by allowing the first person to receive a Spam to add it to the database -- at which point everyone else will automatically block it.

Bayesian Statistics

SpamCan applies Bayesian Statistics against known Spam and not-Spam messages to create new rules "on the fly".


Distributed Checksum Clearing house is a system of many clients and more than 120 servers that collect and count checksums related to several million mail messages per day. SpamCan uses a DCC check to see if the messages have been sent to a large number of users.

All email passing through our SpamCan receives a "Spam score". Email below a certain score, typically 6, is not tagged as Spam and is delivered to the recipient intact. Email that typically scores between 6 and 10 is most probably Spam, but there is a very small chance that it might be real email.

There are four actions that you can take on email that is caught by our

These are :

Temp Fail : SpamCan normally issues an SMTP temporary failure response if a message is held because it is suspected of being spam. This response ensures that the message remains in the sender’s queue.

The sender will retry transmission periodically, until one of three things happens::
  • The message is marked as spam. On the next transmission attempt, it will be rejected with a permanent failure response.
  • The message is marked as not-spam. On the next transmission attempt, it will be accepted and delivered.
  • The sending relay times out and bounces the message. Most relays retry transmissions for at least 3 days, so this will not happen unless you do not check the spam trap often enough.

This is the most recommended method and is set by default.

Modify Subject

Specify a string to insert at the beginning of the subject line, for easy viewing or spotting of Spam messages in your regular inbox. This does not reduce the litter in your mailbox, though you can set Filter rules to sort the spam.


Unlike other solutions which bounce the mail back to the sender intimating it to be identified as spam, this tantamounts to creation of more spam, as you may be bouncing the mail to a false address which spammers craft in mails. Hence the innocent user may consider the bounce as a spam, and blacklist you as well. SpamCan instead rejects mail at the SMTP stage, which means that generation of bounces is the responsibility of the server which is trying to relay the spam to you. This not only avoids you being penalized, but also reduces the queue of undeliverable mails piled up for nonexistent addresses.


This will just delete the email message. You aren't notified, and the sender isn't notified. It's just forgotten about. We don't let the Spam message waste any of our time. Email that scores off our limit-limit, typically over 10, is deleted, but other delivery options are available. The user never needs to be bothered by this "high scoring Spam". It is important to note that these spam scores and delivery options can be adjusted for an entire site, allowing the site administrator to determine what is Spam and what to do with it.

Frequently Asked Questions

1) After I sign up, how soon will the service will be activated?

Typically, within a business day. The primary reason for the delay is that any change to your domain's "MX" records do not take effect immediately, but must propagate through the Internet. Technically, your MX records have a "TTL" (Time-To-Live) value which specifies how quickly changes will take effect. A typical TTL value is one hour, but your domain may be configured with another value, such as 24 hours

2) We don't know how to change the 'MX' Record. What do we do?

That is no problem. We will email you the necessary changes and you can simply forward this email to your hosting company or IT department.

3) How is my email's security and privacy guaranteed?

SpamCan does not affect your email security in any way. Our service does not backup or make copies of your email messages. The log files only contain the email addresses of the sender and the recipient. We will never log the entire email message. We do not share any information with anyone else! In the event your mail server is off-line, our service will "spool" your email messages. When your mail server is back on-line, it will automatically transfer all the spooled email messages. Even in this case, the temporarily spooled messages will not be permanently saved or backed up

4) Does SpamCan add any delay to my incoming mails?

Hardly! This service may delay your email by a few seconds, but not more than a minute. Email with large attachments, especially if you have anti-virus service, can be delayed up to about a minute or so because of the time it takes to do the scanning for viruses and spam.


Email Addresses 0-10 11-25 26-50 51-75 76-100 100+
Rate per user per annum 400 375 350 325 300 275
Slab Cost(Rs.) 4000 9625 18375 26500 34000 -