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dongjianbo-8832 avatar image
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dongjianbo-8832 asked dongjianbo-8832 commented

inbound port 25 is always bolocked for Azure VM

After I created a Azure Windows VM and set inbound role for any to any with port 25, it looks Azure VM blocked the port 25 on Public IP, I created inbound rules for several other ports as well - those work. Only 25 fails to work. appreciated for your help

azure-virtual-machines
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LeonLaude avatar image
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LeonLaude answered dongjianbo-8832 commented

Hi @dongjianbo-883,

Something here might be helpful:

Troubleshoot outbound SMTP connectivity problems in Azure
https://docs.microsoft.com/en-us/azure/virtual-network/troubleshoot-outbound-smtp-connectivity

Here are also other similar threads:

If the reply was helpful please don't forget to upvote and/or accept as answer, thank you!


Best regards,
Leon

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Leon, Thanks for your support. the issue I met is not oubound SMTP but inbound SMTP issue. I set inbound SMTP for 25 and others ports, only failed to telnet with port 25. not sure what's happened. I have asked Azure support team for help. thanks.

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AndreasBaumgarten avatar image
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AndreasBaumgarten answered AndreasBaumgarten edited

Hi @dongjianbo-8832 ,

could you please verify your WM is listening on Port 25 for inbound communication (running one of the command below).

  Get-Process -Id (Get-NetTCPConnection -LocalPort 25).OwningProcess
    
 # or
    
 netstat -a -b

Azure platform is blocking outbound Port 25 (SMTP): https://docs.microsoft.com/en-us/azure/virtual-network/troubleshoot-outbound-smtp-connectivity


(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)

Regards
Andreas Baumgarten

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