---
title: "Sender Policy Framework (SPF) Settings for Sending Emails Using 8x8 Contact Center Internal SMTP Server"
slug: "sender-policy-framework-spf-settings-sending-emails-8x8-contact-center"
updated: 2026-05-11T09:28:58Z
published: 2026-05-21T21:25:40Z
canonical: "help.8x8.com/sender-policy-framework-spf-settings-sending-emails-8x8-contact-center"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://help.8x8.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Sender Policy Framework (SPF) Settings for Sending Emails Using 8x8 Contact Center Internal SMTP Server

## Symptom

Emails are being blocked in 8x8 Contact Center.

## Applies To

- 8x8 Contact Center
- SMTP Server
- Sender Policy Framework (SPF)
- Outbound Emails sent via the 8x8 Contact Center Internal SMTP Server, with the from address on your domain.

## Resolution

One of the following needs to be added the Sender Policy Framework (SPF) record of the domain of the email address you are sending emails from.

either

include:_vccnets.8x8.com

or

ip4:<datacentersubnet>

| Data Center Site | Cluster | IPs |
| --- | --- | --- |
| US West Coast (US1) | NA1-6, NA11-16, NA-21 | 8.21.164.0/24 |
| US East Coast (US2) | NA7-10, NA17-20, NA27-30, NA37-40 | 8.28.3.0/24 |
| Canada (SK1) | CA1-2 | 142.165.219.0/24 |
| Canada Ontario (ON1) | BC1-3 | 50.100.15.0/24 |
| United Kingdom (UK2) | EU2-3 | 217.163.57.0/24 |
| United Kingdom (UK3) | EU4-14 | 109.70.58.0/24 |
| Hong Kong (HK1) | AP1 | 103.252.162.0/24 |
| Australia (SY1) | AU1 | 103.239.164.0/24 |
| LH1 | EU21, EU22 | 152.67.146.53 152.67.146.62 |

> [!NOTE]
> Note:
> 
> Be aware that after adding or modifying your SPF record, DNS propagation can take up to 48 hours to fully update across the internet. While many changes become effective much sooner, it's recommended to allow this timeframe for complete propagation. During this period, some mail servers may still reference the old SPF record, potentially leading to deliverability issues. You can use online DNS propagation checkers to monitor the status of your SPF record update.

## Cause

Failure to add the SPF record can result in emails being blocked and not being received by the recipients.

## Additional Information

[Identify Contact Center Tenant Name and Cluster](/support/docs/identify-contact-center-tenant-name-and-cluster)

Please also see [DomainKeys Identified Mail (DKIM) Settings for Sending Emails Using 8x8 Contact Center Internal SMTP Server](/support/docs/domainkeys-identified-mail-dkim-settings-sending-emails-8x8-contact-center)