What filter uses [VI-1] when blocking email and which company is responsible?
Summary
What email marketers say9Marketer opinions
Marketer from Email Geeks suggests that Synacor might be the filter using '[VI-1]' when blocking mail, and that the 'V' might refer to Vade.
Email marketer from emailadmin.форум shares that the '[VI-1]' filter is commonly associated with email services used by cable companies in Russia and Eastern Europe. They believe Synchronoss provides the infrastructure for some of these services, but direct confirmation is difficult.
Email marketer from StackExchange mentions that identifying specific filter codes like '[VI-1]' often requires detailed analysis of email headers and communication with the receiving mail server's administrator. They suggest looking for consistent patterns in the blocking messages.
Email marketer from Quora highlights the importance of reputation management, SPF, DKIM, and DMARC records to avoid email blocking, and recommends reviewing email compliance.
Email marketer from Reddit suggests that '[VI-1]' could be related to Synchronoss, as they provide email solutions to ISPs. The user indicates this identification is based on observing similar blocking patterns with other ISPs using Synchronoss.
Email marketer from LinkedIn explains that many email security companies partner with ISPs to provide filtering services. Without more data it is hard to confirm but the Expert suggests that the specific implementation and the filter codes used are often customized by the provider.
Email marketer from Blogger notes the importance of reviewing bounce messages and headers from blocked emails to determine the cause, and recommends reaching out to the sender support teams to review the blocks.
Email marketer from DNSqueries.net shares that identifying the specific filter responsible requires reverse DNS lookups on the blocking server's IP address and analysis of the SMTP banner. The user believes this can sometimes reveal the service provider's name.
Email marketer from Email Geeks suggests Synacor might be involved in implementing the '[VI-1]' filter as they provide email solutions to ISPs. The 'V' could refer to Vade, which they are using, but this is speculative.
What the experts say3Expert opinions
Expert from Email Geeks explains that the filter '[VI-1]' is being sent by an MX owned by Synacor and under the covers appears to be coming out of <https://synchronoss.com>.
Expert from Word to the Wise shares how you can find the source of filters. Laura recommends reading the block message and looking at patterns in the headers that might reveal which vendor is responsible for the blocks. Requires deeper research and potentially engaging with the ISP or email provider experiencing the block.
Expert from SpamResource recommends engaging with their support team to investigate specific email blocking issues, highlighting their tools and expertise in analyzing email delivery problems, though they do not offer a direct answer to the '[VI-1]' filter.
What the documentation says6Technical articles
Documentation from Synchronoss confirms they offer email platform services to telecommunications companies and ISPs, which include security and filtering capabilities. It does not specifically mention '[VI-1]', but highlights their comprehensive email management solutions.
Documentation from MessageSystems explains that Momentum (their MTA) can integrate with various filtering solutions. It doesn't specify '[VI-1]', but confirms its platform's flexibility in incorporating third-party or custom filters.
Documentation from Spamhaus explains how IP reputation is key to email delivery, noting poor practices are one of the main reasons providers block mail.
Documentation from RFC specifies how MTAs can use enhanced status codes to provide detailed feedback on why an email was blocked. The documentation explains that the '[VI-1]' could be a vendor-specific code implemented within the enhanced status code.
Documentation from DKIM.org reviews the importance of DKIM and DMARC, including the need to work with your provider to properly implement the technical specifications of DKIM to resolve any blocks.
Documentation from VadeSecure details their use of AI-powered threat detection. While it doesn't reference '[VI-1]', their documentation states they work with ISPs to provide email security services, and the 'V' found in the reference could refer to Vade.