How does Titan Email filter spam?

Titan runs every incoming email through several layers of filtering before it reaches your inbox, checking the sender, validating authentication records, and scanning for spam, viruses, and phishing. Here’s what each layer does, and what happens to your email if it doesn’t pass.

• Postscreen: This is a filter we use that helps us detect if an incoming email is from a spambot or if it contains malware. An email is rejected from delivery if it fails this check.
   
• Sender check: This component detects if the received email has been sent by a valid email server. Sender check will essentially perform a reverse DNS lookup to figure out what is the IP of the received email. If the IP does not point to a valid email server, the email in question will be rejected.
   
• SPF (Sender Policy Framework) check: This component will check the SPF record of the sender domain and validate whether the email is coming from a valid server as mentioned in the SPF record . If the mail is received from an unauthenticated source, the SPF check will perform the action mentioned in the sender domain’s TXT record accordingly as given below:
  1. Hard Fail : The email will be rejected by Titan's servers if it is received from an unauthenticated source
  2. Soft Fail : The email will be accepted by Titan's servers, but it will be tagged as ‘suspicious’ and the recipient will be warned
      
• RBL (Real-time Blackhole List) check: The IP address of an incoming email is run by 2-3 RBL services to verify if the IP has been blacklisted before due to being identified as spammy in nature. Hence. the incoming email will be rejected if the IP is blacklisted.
   
• Open DKIM (DomainKeys Identified Mail) check: If an incoming email's header contains the DKIM Signature, an Open DKIM check will verify the content of the email with the public key published in the DNS record and add the verification result in the Authentication-Results header.
   
• Open DMARC (Domain-based Message Authentication, Reporting & Conformance) check: Open DMARC check will check the status of SPF and Open DKIM checks. Incoming emails will be rejected if they fail the DMARC check, or temporarily failed if the check could not be completed in time. It will add the verification result in the Authentication-Results header
   
• Cmfilter: Cmfilter checks incoming email for spam, viruses, and phishing, using two methods. 
  First, it checks whether the sending IP is a known source of spam — if so, we reject the email immediately. Second, it compares the email’s content against a database of known spam, virus, and phishing signatures
  
  What happens to your email: 
  • Spam: incoming spam is delivered to your spam folder, with the subject line tagged “SPAM.” Outgoing spam is rejected. 
  • Virus: the email is rejected. 
  • Phishing: the subject line is tagged “PHISHING.
   
• Clam SMTP (Simple Mail Transfer Protocol) filter: Clam SMTP filter allows checking for viruses using the ClamAV anti-virus software. Emails with viruses are dropped silently and logged without any additional action taken.
   
• MIME (Multimedia Internet Mail Extensions) header check: MIME header check will essentially check the attachments that have been added to the email. If the file extension format isn't permitted by the incoming email server then the email will be rejected.