Rackspace Technology is a cloud services and hosting solutions provider with over 140000 customers worldwide.
Infrastructure
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Region |
Primarily in the United States, but Rackspace serves customers worldwide. |
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Domains |
mailtrust.com; webmail.us; rackspace.<domain>.<top level domain> |
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Connection and throughput |
Rackspace does not disclose connection and throughput limits. The volume of messages allowed by Rackspace servers may vary depending on your sending reputation and other factors. |
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Complaint feedback loop (FBL) application |
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Postmaster site |
Deliverability best practices and troubleshooting support
- Use opt-in permission methods for all subscribers. Do not purchase email lists or engage in list harvesting from third-party websites.
- Have a list hygiene strategy in place to remove or suppress unknown and unengaged users from your email list.
- SIgn up with the Rackspace complaint feedback loop and suppress all subscribers that complain.
- Configure all IPs with valid reverse DNS (PTR) records.
- Ensure your sending domain has a valid MX record or A record.
- Authenticate all email with SPF, DKIM, and DMARC.
- Implement a prominent unsubscribe link in all email with a one-click unsubscribe process and immediately honor all unsubscribe requests.
- Do not send an executable file (.exe) as an attachment.
- Monitor Rackspace SMTP response codes when encountering delivery issues. The SMTP response codes codes provide additional information to help you troubleshoot.
- If you receive SMTP response codes indicating you are exceeding connection and throughput limits, reduce the number of connections, email volume, and increase retry times until the messages are no longer received.
- Deploy different mailstreams (e.g. transactional and marketing mail) from different IP addresses and From addresses.
- Warm up new IP addresses by sending 20 messages per day to establish a sending reputation. Rackspace does not specify when to increase volume, so slowly increase volume every few days and closely monitor error and bounce codes for signs of throttling or blocks.
- Look up and delist all IPs and domains from the following blocklists, including any third party domains. Be sure to fix the cause of any blocklistings prior to submitting a delisting request or listings will recur.
Mediation
- For delivery assistance, send an email to: postmaster@emailsrvr.com. Be sure to include all relevant information regarding your delivery issues, including IP address, sending domain, summary of the issue, and all steps taken to resolve the issue.
