Have you ever wondered what the email delivery chain looks like - and the trouble each link can cause in getting your marketing message to its final destination? Here's a look at the process according to ClickZ.
1. The sender. It all starts here. How you manage everything - content creation, list management, sending protocol - shapes your deliverability.
2. E-mail service provider (ESP) or e-mail software. Low-grade e-mail software and bargain-basement ESPs are more likely to be associated with spammers, and you can get smirched by association.
3. Mail transfer agent (MTA). This application forwards your e-mail to either the recipient's ISP or another MTA.
4. Outbound ISP. Some marketers still send bulk e-mail from personal e-mail clients. ISPs could assume computers have turned into spam-spewing zombies and block anything they send.
5. Edge networks. Companies such as Postini, Barracuda, and Brightmail sit on the edge of the receiving ISP's connection and filter incoming traffic .
6. Receiving ISP. This link can stop you cold if you don't follow e-mail best practices. It comprises:
- ISP reputation system. Monitors your IP address for the number of user complaints.
- Authentication codes. These tell inbound servers you're either authorized to send from your domain or IP addresses or you are whom you claim to be.
- Internal/external blacklists. These include in-house blacklists of addresses, domain names, and IP addresses users reported as spam.
- Internal/external whitelists.
- ISP filters. These block e-mail with spammy content, malicious exe files, and unverified senders.
- Third-party filters. SpamAssassin and similar programs analyze an e-mail's content, design, coding and can reject for failed tests.
- Challenge/response. This system-wide identity check aims to stop unsolicited e-mail generated by automated programs like random-address generators or harvesters.
- Corporate firewalls and third-party filters.
- Corporate e-mail servers. Like the ISP's servers, these use blacklists, whitelists, and filters to allow trusted senders and content while keeping suspect ones out.
7. Recipients. To round out the journey, recipients use junk-detecting devices and delete e-mail they either don't trust or don't feel like opening and employ E-mail client default settings and filters, User settings and filters, Third-party anti-spam filter programs, Another round of Challenge/response, "Report spam" button andBulk/spam folders.
