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Some incoming e-mails are not delivered

Discussion in 'E-mail Discussions' started by postcd, Jan 16, 2018.

  1. postcd

    postcd Well-Known Member

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    Hello,

    i tried to use yahoo, centrum.cz, bitmessage.ch free mailboxes to send e-mail to couple of my cPanel accounts on my WHM server. Previously i have not noticed problems with mail delivery, but now i see i do not receive some e-mails.

    I checked the server logs:
    cd /var/log;grep -E "yahoo|centrum|bitmessage|mycpaneldomain1|mycpaneldomain2" maillog exim_mainlog

    and i found delivery from some servers, but not from those that i mentioned above. Unsure if that two logfiles are everything i need to check.

    i asked centrum.cz admin if they can send me details on delivery failure cause

    yahoo shown delivery failure e-mail but after studying its headers/source code i have not found any reason beside nothing saying "Unable to deliver message after multiple retries, giving up."

    bitmessage shows: "Error Type: SMTP Error Description: Unable to find the recipient's email server. The DNS query has failed."

    I checked and the cPanel VPS is using Google DNS and VPS host server is using opennic NSs in /etc/resolv.conf:
    nameserver 185.121.xxx.xxx
    nameserver 185.121.xxx.xxx
    they seem to work.

    When i disabled ConfigServerFirewall (csf -x) and tried to send e-mail again, the e-mails reached the mailserver as per the logs here
    One from bitmessage was denied by SpamAssasin and deleted and other from yahoo went thru - OK. But when i check CSF and iptables output for the IPs of that remote mailservers, these were not blocked and also no subnet to the first octet 123.*.*.*, i checked all logs in /var/log (grep -ER "146.228.112.|66.163.187." /var/log) including lfd.log (firewall log) and the IPs was not found (except entries fot the time i disabled firewall). When i re-enabled firewall (csf -e) at least some (2/3) e-mails seems to be going thru (maybe temporary IP blocks was removed), but some mails are still not delivered to my mail server (nothing in the mailserver logs). Firewall log do not appear to show any IPs banned.

    Do You have any idea please which tools to use to find the cause of delivery failure?
     
    #1 postcd, Jan 16, 2018
    Last edited: Jan 17, 2018
  2. Infopro

    Infopro cPanel Sr. Product Evangelist
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  3. postcd

    postcd Well-Known Member

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    Thanks, but i do not think it helps me in any way. If the mail would be denied by my server as a spam, i would see it in logs right?
    I got score 6/10 on that site, "The famous spam filter SpamAssassin. Score: -3.5. A score below -5 is considered spam."
    Infopro, i hope you can try to answer questions i raised in my initial post so i can discover which cpanel services, logs i need to check, where to enable debug logging, how to trace what happen with e-mail exactly, where it is denied. This do not look like bad spam score. And my server IP is not listed on major blacklists. Thank You
     
    #3 postcd, Jan 17, 2018
    Last edited by a moderator: Jan 17, 2018
  4. Infopro

    Infopro cPanel Sr. Product Evangelist
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    Mail to you, is failing, as I understand your post. I'm unable to assist you using opennic, I don't know anything about it.
     
  5. postcd

    postcd Well-Known Member

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    i see, i will need to wait for other cPanel staff or member and also i am searching Google for possible ways in the meantime.
     
  6. cPanelMichael

    cPanelMichael Forums Analyst
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  7. postcd

    postcd Well-Known Member

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    Thank you for your reply. I read yours linked topic, they suggest IPv6 enable, but my VPS does not support IPv6 at all. Moreover i do not believe firewall blocked the mailserver IPs because i went thru the logs as i mentioned. And i did it again just now and i see there was just like 3 permanent firewall blocks for last 3 days and there are only 4 temporary IP blocks, i checked these few IPs in whois to see its owner and detail and these are not mail servers. Though, out of 3 e-mails i sent before 20 minutes (from bitmessage freemail, centrum.cz freemail, yahoo.com freemail) only one appeared in logs for last 20 minutes since i sent e-mails. Others not appeared, not delivered.

    The one that appeared in logs was marked as spam: ""SpamAssassin as cpusernamehere detected message as spam (8.4)"" - by the way this seems strange to me, because my subject was: testab, body was: testab
    I believe such testing e-mail should be delivered and i am curious how i can setup SpamAssassin not to mark such testing e-mails as SPAM.

    Other question is why it not delivered other two e-mails and there i ask if anyone is willing to suggest some approach on how to test the things and discover cause. Offcourse i would be very grateful and it may help me and other people in future.
     
  8. cPanelMichael

    cPanelMichael Forums Analyst
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    Hello,

    You may also want to review /var/log/exim_rejectlog to see if there are any entries there for the emails that were not delivered. EX:

    Code:
    exigrep user@domain /var/log/exim_rejectlog
    Additionally, this thread is a useful reference:

    Reading and Understanding the exim main_log

    I encourage you to open a separate thread for additional issues (e.g. SpamAsssasin rules) unrelated to this particular topic so we can better assist you.

    Thank you.
     
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