SMTP Telnet Troubleshooting
Posted on 2013-10-24
Very easy question, should you always be able to "telnet mailservername 25" to a companys email server?
I have a company I'm trying to email and get a bounce back saying;
"A problem occurred during the delivery of this message to this e-mail address. Try sending this message again. If the problem continues, please contact your helpdesk."
"mailserver.domain.com #550 Invalid recipient <email@example.com> (#5.1.1) ##"
Their Internet facing Exchange 2010 SMTP server should be configured on port 25 and allow anonymous connections correct?
1. I used nslookup to find their mx record (mail.domain.com)
2. Tried the telnet command from my exchange server to theirs:
C:\>telnet mail.domain.com 25
Connecting To mail.domain.com...Could not open connection to the host, on port 25: Connect failed
Does this tell me that they need to check their side or am I missing something?
Both sides are Exchange 2010.
Thanks in advance.