Postfix relay to Office 365 external recipients not delivered

Posted on 2013-01-29
Last Modified: 2013-02-19
I have an issue with Postfix relay to MS Office 365. I can send to internal addresses, but not external. I receive the following error message:

550 5.7.1 Client does not have permissions to send as this sender (in reply to end of DATA command))

I have setup a Microsoft SMTP server and it works fine, both internal and external, but Postfix will not deliver to external addresses. I know it has to be a configuration issue. I just can't pinpoint what it is. I really would prefer to use Postfix. I've used it before and never had any issues, but if I don't figure this out, I will have to go with MS

Here is my

# See /usr/share/postfix/ for a commented, more complete version

# Debian specific: Specifying a file name will cause the first
# line of that file to be used as the name. The Debian default
# is /etc/mailname.
myorigin = /etc/mailname

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

readme_directory = no

# TLS parameters
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.

myhostname =
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination =,, , localhost
relayhost = []:587
mynetworks =, [::ffff:]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +

inet_interfaces = all

smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_tls_CAfile = /etc/postfix/cacert.pem

smtp_generic_maps = hash:/etc/postfix/generic
smtp_sasl_mechanism_filter = login
smtp_tls_loglevel = 1
smtp_tls_security_level = may
smtp_send_dummy_mail_auth = yes
Question by:shart68
1 Comment
LVL 37

Accepted Solution

ArneLovius earned 500 total points
ID: 38833680
I would guess that you had a username and password for the smarthost in the Microsoft SMTP relay.

Rather than relay through Office 365, why not just add your exit address to your SPF record and send direct ?

Featured Post

Master Your Team's Linux and Cloud Stack!

The average business loses $13.5M per year to ineffective training (per 1,000 employees). Keep ahead of the competition and combine in-person quality with online cost and flexibility by training with Linux Academy.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Scam emails are a huge burden for many businesses. Spotting one is not always easy. Follow our tips to identify if an email you receive is a scam.
How to resolve IMCEAEX NDRs in Exchange or Exchange Online related to invalid X500 addresses.
In this Micro Video tutorial you will learn the basics about Database Availability Groups and How to configure one using a live Exchange Server Environment. The video tutorial explains the basics of the Exchange server Database Availability grou…
Get a first impression of how PRTG looks and learn how it works.   This video is a short introduction to PRTG, as an initial overview or as a quick start for new PRTG users.

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question