Unable to Connect to SMTP on Azure Ubuntu Server for Gmail: Port 25 Telnet Issue

Question

Unable to Connect to SMTP on Azure Ubuntu Server for Gmail: Port 25 Telnet Issue

Shanuka Thushara 61

Hello everyone, I've been trying to connect to SMTP on my Azure Linux VM, specifically to Gmail. However, I'm facing an issue as it says "unable to connect." I used the command telnet smtp-relay.gmail.com 25. Please note that I have allowed port 25 in both my Network Security Group (NSG) and Azure VM firewall settings, yet the problem persists. I would appreciate any advice or guidance on resolving this issue with my Azure VM. smtp error

Prrudram-MSFT 28,206 Reputation points Moderator

2024-01-22T09:54:08.3666667+00:00

Hi @Shanuka Thushara

The Azure platform blocks outbound SMTP connections on TCP port 25 for deployed VMs. This block is to ensure better security for Microsoft partners and customers, protect Microsoft’s Azure platform, and confirm to industry standards. As suggested by Andreas in his answer, if you're using a subscription type that isn't an Enterprise Agreement or MCA-E, we encourage you to use an authenticated SMTP relay service, as outlined earlier in this article. If an answer has been helpful, please consider accepting the answer to help increase visibility of this question for other members of the Microsoft Q&A community. If not, please let us know what is still needed in the comments so the question can be answered. Thank you for helping to improve Microsoft Q&A!

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Prrudram-MSFT 28,206 Reputation points Moderator

2024-01-22T09:54:08.3666667+00:00

Hi @Shanuka Thushara

The Azure platform blocks outbound SMTP connections on TCP port 25 for deployed VMs. This block is to ensure better security for Microsoft partners and customers, protect Microsoft’s Azure platform, and confirm to industry standards. As suggested by Andreas in his answer, if you're using a subscription type that isn't an Enterprise Agreement or MCA-E, we encourage you to use an authenticated SMTP relay service, as outlined earlier in this article. If an answer has been helpful, please consider accepting the answer to help increase visibility of this question for other members of the Microsoft Q&A community. If not, please let us know what is still needed in the comments so the question can be answered. Thank you for helping to improve Microsoft Q&A!