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Paubox IP addresses for allowlisting

Use this page when you need to let Paubox through a firewall, a spam filter, or a mail flow rule. These are the IP addresses for Paubox Email Suite. Copy them exactly as shown.

Incoming mail (Inbound Security)

When Inbound Security is on, Paubox scans your incoming email and then delivers it to your email provider or mail server from the addresses below. Use them in your Microsoft 365 mail flow rule or connector, your Google Workspace inbound gateway, or your firewall.

The list you need depends on your domain’s MX record. You can find your MX record in your domain host’s DNS settings.

If your MX record is mx.paubox.com

  • 165.140.171.0/24

If your MX record is mx1.paubox.com (older accounts)

  • 54.69.65.158
  • 54.69.73.61
  • 54.69.172.93

If your MX record is mx2.paubox.com (older accounts)

  • 52.26.137.1
  • 52.26.86.178
  • 52.26.218.15

If your own mail server only accepts connections from certain addresses, allow the addresses for your MX record on port 25.

Outgoing mail (Outbound Security)

Paubox sends your outgoing email from the addresses below. They are also the addresses behind outbound.paubox.com, the server your email platform sends to.

  • 165.140.171.0/24
  • 52.27.124.21
  • 52.11.246.83
  • 52.25.230.42

Use this list when:

  • A partner or recipient asks which IP addresses your email comes from
  • Your firewall limits outgoing connections from your own mail server (allow connections to these addresses on port 25 or 587)

Sending from your own mail server

If you send through Paubox from Google Workspace or Microsoft 365, you don’t need to add anything on the Paubox side.

If you send from your own mail server, such as Microsoft Exchange Server, send your server’s public IP address to Paubox Support. Paubox accepts mail based on the IP address it comes from, so your address has to be added before your mail can go through.

SPF

For your SPF record, use include:_spf.paubox.com instead of listing these IP addresses. See Paubox DNS records: MX, SPF and DKIM.

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Questions? Contact Paubox Support. We're here to help!