IPs for Firewalls

Below is a list of IPs you can add to your firewall for sending email through SMTP, Inbound processing and Webhooks.

Outbound SMTP Servers

The IP addresses that Transactional and Broadcast messages are sent from.

• 50.31.156.96/27 (50.31.156.96 - 127) [Transactional]
• 104.245.209.192/26 (104.245.209.192 - 255) [Transactional]
• 50.31.205.204/30 (50.31.205.204 - 207) [Transactional]
• 50.31.205.0/24 (50.31.205.1 - 255) [Broadcast]

SMTP Endpoints

The IP endpoints for accessing SMTP outbound.

CIDR Blocks / Ranges

• 147.75.195.176/30 [147.75.195.176 - 147.75.195.179]
• 147.75.202.84/30 [147.75.202.84 -147.75.202.87]
• 147.75.205.84/30 [147.75.205.84 - 147.75.205.87]

• 52.79.88.220
• 54.180.186.193
• 34.249.162.51
• 52.208.184.61
• 63.35.51.189
• 3.208.98.158
• 3.93.205.235
• 3.95.122.1
• 3.208.98.158
• 3.93.205.235
• 3.95.122.1
• 13.209.189.43
• 15.164.159.110
• 52.208.94.138
• 52.210.34.36
• 54.77.222.65

Note: IP allowlisting for our API is no longer supported. Learn more

Inbound SMTP Servers

These IPs are where Postmark's inbound MX record points.

• 13.58.75.120
• 52.36.8.247
• 18.221.96.15
• 34.211.250.229
• 34.211.88.250
• 18.221.180.145
• 52.210.157.196
• 52.213.211.243
• 52.51.73.41
• 13.125.126.102
• 3.34.204.228
• 3.34.213.247
• 107.22.71.110
• 52.2.5.255
• 72.44.42.226

Webhooks

These IPs apply for every webhook sent by Postmark (inbound, bounce, open, etc).

• 3.134.147.250
• 50.31.156.6
• 50.31.156.77
• 18.217.206.57