Enable IPV6 for POSTFIX outgoing mail (SMTP)

Discussion in 'General' started by c3n, Sep 14, 2021.

  1. c3n

    c3n Member

    I got several dedicated servers on OVH with failover IPs for VPS KVM. Most of IPV4 IP ranges are with good reputation. But lately I bought several single failover IPS and small ranges... and most of them are in OUTLOOK blacklist bouncing email. My email settings score is 10/10 (DKIM, SPF, DMARC)... everything OK. So i stucked because OVH cannot provide me more single IPs with 100% good reputation (Microsoft added most of their IP ranges to blocklist and dont want to remove)... so OVH technician told me that solution is to send emails via IPV6 IP. So my question is:
    1) what are your experiences and are there any contraindications to send emails via IPV6? most of topics here are how to disable IPV6 in postfix :(
    2) how to setup POSTFIX to send emails only via IPV6.

    For this setup I can build VPS from scratch that is why i dont give any information about system (mostly Debian 9/10)...

    Waiting for Your kindly reply.


    Why I need single failover IPs? because some servers/clients need to be scalable and fast migrate to different server scenarios... single failover can be moved between servers without any problems within minutes... those IPs with good reputation are in 12/24 ranges and all must be moved. It is also good to have failover for disaster recovery scenarios... that is why i am trying to solve this issue.
  2. Th0m

    Th0m ISPConfig Developer Staff Member ISPConfig Developer

    My first advice would be not to use OVH for your mailservers ;)

    You can use IPv6, but there are many IPv4 only mailservers, including the Outlook servers as far as I know. So that does not solve your issue. Instead, get in touch with them and tell them that you are the new owner of those IP's and it's unlawful to block them just because they can.

    I send them something like this in the past: "Outlook.com just marks all email from new IP adresses as spam. This way, it is impossible to properly start a ESP. As said before, this is against dutch law, because you suppress small businesses. Please review your policy's."
    They replied in no time and suddenly they would reset the IP reputation.
    ahrasis likes this.
  3. c3n

    c3n Member

    Hello Th0m!
    Thanks for clarifying... I abandon IPV6 idea and for now I will try to get new IPs from OVH and check them (a minute ago got another range of IPs). PLAN B is to split services so I will keep mailservers for clients on clear IPs... once again many thanks for fast reply.

    Regards, Maciej
  4. c3n

    c3n Member

    I also joined Junk Mail Reporting Program (JMRP) for some of my servers...
  5. c3n

    c3n Member

    OK, I know how to clean reputation of IP blocked by outlook protection, here is error message:

    So I cleared several IPs it took me 2-3 weeks. Steps:
    1) post removal request > New support request (microsoft.com)
    you will receive auto message that
    2) you must answer on this email asking to clear IP reputation with the following informations:
    a) Submit as attachement invoices for IP ranges,
    b) write that You are aware of spam problem and there was no spaming activity for month because IP was not used (my problem was with new IPs)
    c) tell them that servers are managed by IT staff
    d) ask them to check IP whois that it is Yours company and You are legally operating company.
    3) You will receive auto reply with TICKET and after few days propably real person will write to you that issue is under investigation. Write them back that you will provide all the information they need, because the outblook block prevents your company from operating.
    4) after 1-2 weeks they will write to you that:
    I already checked and IPs blocked are unblocked now and reaching hotmail.com.

    Regards, M
    brunoa likes this.
  6. c3n

    c3n Member

    to prevent hotmail/outlook block join JMRP.
  7. brunoa

    brunoa New Member

    Thank you, I'm a 1-user ISPConfig installation but I'm in the same context. Thank you for your help regarding microsoft/outlook/hotmail, it helped a lot !
    My challenge now it to do the same with google / gmail servers, that put all my emails in SPAMS for the same reason.
    To be Continued
    Th0m likes this.
  8. Th0m

    Th0m ISPConfig Developer Staff Member ISPConfig Developer

    This might help: https://www.howtoforge.com/communit...ility-to-google-mail-users.86369/#post-418089
    brunoa likes this.

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