Category: smtp
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Finding Existing Plus Addresses
Exchange Online will automatically enable “Plus Addressing” for all tenants from Jan 2022. This change may cause issues if you have existing mailboxes where the SMTP address contains a + sign. That is, directors+managers@contoso.com would be considered a broken email address from Jan 2022 in Exchange Online. So you need to check you have no…
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Enabling Better Mail Flow Security for Exchange Online
At Microsoft Ignite 2020, Microsoft announced support for MTA-STS, or Mail Transfer Agent Strict Transport Security. This is covered in RFC 8461 and it includes making TLS for mail flow to your domains mandatory whereas it is currently down to the decision of the sender. You can publish your SMTP endpoint and offer the STARTTLS…
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Mail Flow To The Correct Exchange Online Connector
In a multi-forest Exchange Server/Exchange Online (single tenant) configuration, you are likely to have multiple inbound connectors to receive email from the different on-premises environments. There are scenarios where it is important to ensure that the correct connector is used for the inbound message rather than any of your connectors. Here is one such example.…
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Anonymous Emails Between On-Premises and Exchange Online
When you set up Exchange Hybrid, it should configure your Exchange organizations (both on-premises and cloud) to support the fact that an email from a person in one of the organizations should appear as internal to a recipient in the other organization. In Outlook that means you will see “Display Name” at the top of…
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420 4.2.0 RESOLVER.ADR.Ambiguous; ambiguous address
This error can turn up in Exchange Server when Exchange Server is trying to resolve the object that it should deliver a message to. Exchange queries Active Directory and expect that if the object exists in the directory, that the object exists only once. If the object exists more than once, this is the error…
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Journal Rule Testing In Exchange Online
I came across two interesting oddities in journaling in Exchange Online in the last few weeks that I noticed where not really mentioned anyway (or anywhere I could find that is). The first involces routing of journal reports and the second the selection of the journal target. The journal report, that is the message that…
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Speaking at TechEd Europe 2014
I’m please to announce that Microsoft have asked me to speak on “Everything You Need To Know About SMTP Transport for Office 365” at TechEd Europe 2014 in Barcelona. Its going to be a busy few weeks as I go from there to the MVP Summit in Redmond, WA straight from that event. My session…
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Highly Available Office 365 to On-Premises Mail Routing
This article looks at how to configure mail flow from Office 365 (via Exchange Online Protection – EOP) to your On Premises organization to ensure that it is highly available and work in disaster recovery scenarios with no impact. It is based on exactly the same principle to that which I blogged about in 2012:…
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Domain Secure and Edge Servers
I was asked a question recently on the Microsoft Certified Master course for Exchange 2010 and was told that the answer was not clearly written up on the internet. So I thought I would write this blog post. The question was based on the idea that Domain Secure worked from a Hub Transport server in…
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Exchange 2013 Transport Agents
Earlier today I posted http://blog.c7solutions.com/2012/10/creating-simple-exchange-server.html on how to create a transport agent in Exchange, and though the steps cover some of the detail for Exchange Server 2013 they do not cover some of the detail, so I’ve added that to this post below: Use .NET Framework 4.0 for Exchange 2013 though it is possible to…
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Creating a Simple Exchange Server Transport Agent
This blog post follows a session that I delivered at the MEC 2012 conference in Orlando. If you attended the conference the slides are available on http://mymec.mecisback.com for the rest of 2012. Part of the transport agents session was writing a new transport agent, and the example agent was to do add a form of…
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Creating GeoDNS with Amazon Route 53 DNS
UPDATE: 13 Aug 2014 – Amazon Route 53 now does native GeoDNS within the product – see Amazon Route 53 GeoDNS Routing Policy A new feature to Exchange 2013 is supported use of a single namespace for your global email infrastructure. For example mail.contoso.com rather than different ones for each region such as uk-mail.contoso.com; usa-mail.contoso.com…
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McAfee Total Protection and SMTP Email on Port 587
McAfee blocks SMTP connections that do not operate on the default port 25. If you have Outlook, Outlook Express, Windows Mail or Windows Live Mail configured to use an SMTP port that is not 25 then you get errors such as: Your server has unexpectedly terminated the connection. Possible causes for this include server problems,…