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]
• 50.31.205.0/24 (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