O postfix IPv6 pode receber e-mails, mas não pode enviar

Question

Eu instalei o postfix mta e configurei para trabalhar com o IPv6. Testei enviando um e-mail do gmail para o meu vps e o e-mail foi recebido, mas quando eu quero enviar um e-mail para o gmail eu recebo o tempo limite como abaixo:

Sep  6 05:55:59 vpsunder10 postfix/smtp[9613]: connect to gmail-smtp-in.l.google.com[2607:f8b0:4002:c01::1b]:25: Connection timed out
Sep  6 05:56:29 vpsunder10 postfix/smtp[9613]: connect to alt1.gmail-smtp-in.l.google.com[2607:f8b0:400c:c02::1a]:25: Connection timed out
Sep  6 05:56:59 vpsunder10 postfix/smtp[9613]: connect to alt2.gmail-smtp-in.l.google.com[2a00:1450:400c:c03::1b]:25: Connection timed out
Sep  6 05:57:29 vpsunder10 postfix/smtp[9613]: connect to alt3.gmail-smtp-in.l.google.com[2a00:1450:4013:c01::1b]:25: Connection timed out
Sep  6 05:57:59 vpsunder10 postfix/smtp[9613]: connect to alt4.gmail-smtp-in.l.google.com[2a00:1450:4001:c02::1b]:25: Connection timed out

Como eu vejo nos logs, o MTA tenta se conectar na porta 25, que acho que está fechada. Alguma idéia qual é o problema?

    

Answer 1

A porta 25 é de fato filtrada pelo HE.net por causa de abuso. Veja o este tópico . Para referência, colei o post abaixo:

Due to an increase in email abuse, new non-BGP tunnels now have SMTP blocked by default. If you are a Sage, you can re-enable SMTP by visiting the tunnel details page for that specific tunnel and selecting the 'Unblock SMTP' option under the Advanced tab. Because this is now also being abused, we've disabled SMTP for new accounts for now, and the Sage removal is not available for those. If you need SMTP (tcp/25), please email [email protected] and explain your need for it. SMTP-MSA (tcp/587) is unaffected. Existing tunnels have not been filtered.

This does not affect certification e-mail tests, since that traffic is still explicitly permitted.

Here's the matrix of how the blocking is implemented, since people seem to be a little confused. Account Date Tunnel Date Certification Level SMTP Status Before this post Before this post Any Not filtered Before this post After this post Not Sage Filtered Before this post After this post Sage Option to unfilter under 'Advanced' After this post n/a Not Sage Filtered. Contact [email protected] if needed, with your use justification. Do note, non-Sages will likely need more detailed justification. After this post n/a Sage Filtered. Contact [email protected] as above, with your use justification.