IP Addresses

We recommend that you configure your router, firewall, or mail server to only accept incoming mail from our range of IP addresses. This prevents spammers from sending mail directly to your server, thus bypassing the MX Guardian servers. Our current list of IP addresses are:

IPv4 Addresses

52.202.8.242
54.235.79.122
54.84.69.64
54.84.72.194
54.84.55.19
54.84.86.117
54.84.107.183
54.84.110.207

IPv6 Address Range

2600:1f18:260a:1a00::/56


You should block inbound connections on port 25 from all IP addresses EXCEPT those listed above. If your mail server hosts multiple domains, make sure all the domains are routed through MX Guardian before adding any firewall rules. Please contact us if you have any questions.