If you are connecting to one of these IPs your connection may timeout. You may also configure your outbound email server to do a round-robin DNS lookup for
We may not accept email from senders who fail a reverse-DNS lookup.
Senders must not use namespace mining techniques against inbound email servers.
This is the practice of verifying email addresses without sending (or attempting to send) emails to those addresses.
If you are able to connect directly to the IP and not mail.hotmail.com, then it is likely there is an issue with your DNS server.
Occasionally, some of the IPs in our MX record may be out of service.
Once the IP has built a reputation for not sending spam, will typically allow for a better email delivery experience.We will do our best to help you troubleshoot your issue.However, submitting this information does not guarantee that any message you send to users of the services will be delivered.If you are running anti-virus software on your firewall or SMTP server, check for the setting "Internet Email Auto Protect" or "Internet Email Protection." If this setting is enabled, disable it and try sending a test message to our servers again. If you are unable to connect, then attempt to telnet over port 25 directly to our email servers (MTAs).
You can find the current list of our MTAs by querying "nslookup –q=mx hotmail.com" from a command prompt (this should work in a variety of Operating Systems).We also leverage SPF , an email authentication technology protocol that helps address the problem of spoofing and phishing by verifying that the domain sending the email is authorized to do so.