Whitelisting Our IP Addresses With Your Incoming (MX) Server

This page is a little technical, so if you are unsure what whitelisting is, be sure to read our blog post on whitelisting first. We also have additional information on whitelisting for Office 365 users here.

SMTP2GO sends out emails from a range of different IP addresses. The current IP addresses we use can always be found by looking at the SPF record for spf.smtp2go.com:


On the above page, you will see a series of IP address ranges, in the following format:
ip4:xyz.xyz.xyz.xyz/nn (this is called CIDR format)

If it is possible, it is often a good idea to have your incoming (MX) mail server whitelist the IP ranges shown on the above page.

The benefits of whitelisting with your incoming mail server include:

  • automatically bypassing unnecessary spam filters (as you have sent the emails, they shouldn't need to be scanned).
  • automatically bypassing any blacklist checks (just in case any IP address ever features on a blacklist).

If you wish to be notified whenever we add new IP addresses, please subscribe to this page.

Most recent update (December 2018): The outbound IP range has been added.

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