use smtp.mydomain.com or mail.mydomain.com

Do I use smtp.mydomain.com or mail.mydomain.com to send emails from my third party application?
I have SBS server and exchange is working as it should, we use a third party application which sends emails to clients with a PDF invoice.  There are no notes.
If I use smtp and smtp.gmail.com port: 587 the emails work but if I use smtp mail.mydomain.com port 25 it does not work.  Port 25 is open.
Should I be using smtp.mydomain.com port 25?
Apologies if its a dumb question.
ScorpioManAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

WORKS2011Austin Tech CompanyCommented:
Should I be using smtp.mydomain.com port 25?
no, not if the application is working using port 587. Some IPS's block 25 for sending email to fight spam, it uses port 587 so your ISP doesn't think the third party app is a spam relay.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
I QasmiTechnical LeadCommented:
smtp.mydomain.com port 25 and 587 both are used for mailflow

port 587 is used in case you have a smarthost for mailflow / or for security reasons

and if your application is working  on 587 its fine, let it work on 587
0
Milan_rCommented:
If the mail is going from  third party application ans it's working then keep opn using port 587 as it secure.
0
ScorpioManAuthor Commented:
thanks for the quick response
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Microsoft Server OS

From novice to tech pro — start learning today.