Office 365 SMTP server not advertising StartTLS
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Tested using same application but on different computer and network, works without any issue.
Need to verify whether or not it's only happening on one of the computers on their network.
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Could it be TLS 1.2 is not set as the default on the client system? If it is Windows 7, you need to adjust some registry entries.
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@wrx7m said in Office 365 SMTP server not advertising StartTLS:
Could it be TLS 1.2 is not set as the default on the client system? If it is Windows 7, you need to adjust some registry entries.
The one email library will only use a maximum of TLS 1.0. And it is before the TLS handshake, so I wouldn't think that TLS version would be a consideration yet.
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@flaxking said in Office 365 SMTP server not advertising StartTLS:
@wrx7m said in Office 365 SMTP server not advertising StartTLS:
Could it be TLS 1.2 is not set as the default on the client system? If it is Windows 7, you need to adjust some registry entries.
The one email library will only use a maximum of TLS 1.0. And it is before the TLS handshake, so I wouldn't think that TLS version would be a consideration yet.
OK, because they started forcing TLS 1.2 back in October.
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@wrx7m said in Office 365 SMTP server not advertising StartTLS:
@flaxking said in Office 365 SMTP server not advertising StartTLS:
@wrx7m said in Office 365 SMTP server not advertising StartTLS:
Could it be TLS 1.2 is not set as the default on the client system? If it is Windows 7, you need to adjust some registry entries.
The one email library will only use a maximum of TLS 1.0. And it is before the TLS handshake, so I wouldn't think that TLS version would be a consideration yet.
OK, because they started forcing TLS 1.2 back in October.
Nope, they've updated that notice
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@flaxking Guess we are thinking of different notices... https://support.microsoft.com/en-us/help/4057306/preparing-for-tls-1-2-in-office-365
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@wrx7m "Note This doesn't mean Office 365 will block TLS 1.0 and 1.1 connections. There is no official date for disabling or removing TLS 1.0 and 1.1 in the TLS service for customer connections."
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@flaxking Gotcha. But, it has caused issues depending on how you are connecting and what you are connecting with. I had issues connecting with Windows 7 and Outlook and was told by support to apply registry fix and make sure a certain update was applied.
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Isn't the list of SMTP commands given before there is any attempt to bring up a TLS tunnel? Assuming my understanding of that is correct - then it shouldn't matter what version of TLS is supported - the advertising of STARTTLS should still be in the list - and the library's aren't seeing them - right?
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From what I heard from our tech, it sounds like the company's UTM was messing with it.
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@flaxking said in Office 365 SMTP server not advertising StartTLS:
From what I heard from our tech, it sounds like the company's UTM was messing with it.
That's quite possible. UTMs can introduce a lot of problems.
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@scottalanmiller said in Office 365 SMTP server not advertising StartTLS:
@flaxking said in Office 365 SMTP server not advertising StartTLS:
From what I heard from our tech, it sounds like the company's UTM was messing with it.
That's quite possible. UTMs can introduce a lot of problems.
LOL I was going to say the same thing...
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@flaxking said in Office 365 SMTP server not advertising StartTLS:
From what I heard from our tech, it sounds like the company's UTM was messing with it.
Which UTM? Hopefully not SOnicwall in this case.
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@dbeato said in Office 365 SMTP server not advertising StartTLS:
@flaxking said in Office 365 SMTP server not advertising StartTLS:
From what I heard from our tech, it sounds like the company's UTM was messing with it.
Which UTM? Hopefully not SOnicwall in this case.
Hopefully it IS SonicWall, so that all these stupid issues can be isolated to one bad vendor rather than sprawling across the industry.
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@scottalanmiller said in Office 365 SMTP server not advertising StartTLS:
@dbeato said in Office 365 SMTP server not advertising StartTLS:
@flaxking said in Office 365 SMTP server not advertising StartTLS:
From what I heard from our tech, it sounds like the company's UTM was messing with it.
Which UTM? Hopefully not SOnicwall in this case.
Hopefully it IS SonicWall, so that all these stupid issues can be isolated to one bad vendor rather than sprawling across the industry.
They are not the only one as I can mention many....
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No idea, we don't manage the client's infrastructure
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@flaxking said in Office 365 SMTP server not advertising StartTLS:
No idea, we don't manage the client's infrastructure
Then it was definitely the UTM, no question.
