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Exim Email Problem: 450 4.7.1 Client host rejected: cannot find your reverse hostname

Discussion in 'E-mail Discussion' started by m0rpheu5, Jul 20, 2011.

  1. m0rpheu5

    m0rpheu5 Well-Known Member

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    Hello guys, i´m having problems, to send email for some email providers, in all cases that the message stay on my mail queue for 48-72h i got this message when i try to deliver it now:

    450 4.7.1 Client host rejected: cannot find your reverse hostname

    What could be? i Have RDNS, SPF, DomainKeys, and i don´t know what could be anymore.

    Could anybody help me to fix this issue?

    Thanks
     
  2. Infopro

    Infopro cPanel Sr. Product Evangelist
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    Re: Exim Email Problem: 450 4.7.1 Client host rejected: cannot find your reverse host

    Might be easier to assist with the actual domain name posted. If thats not possible you may want to open a ticket to your host or contact cPanel directly.
     
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  3. m0rpheu5

    m0rpheu5 Well-Known Member

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    Re: Exim Email Problem: 450 4.7.1 Client host rejected: cannot find your reverse host

    my actual domain is icnetwork.com.br, many of the clients that i´m sending is hosted in the Locaweb provider (locaweb.com.br), but sometimes i got the same problem with users that is not hosted on there, but normally is.

    Thanks
     
  4. Infopro

    Infopro cPanel Sr. Product Evangelist
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    Re: Exim Email Problem: 450 4.7.1 Client host rejected: cannot find your reverse host

    /http://www.intodns.com/icnetwork.com.br

    There does seem to be an issue with the domain.
     
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  5. m0rpheu5

    m0rpheu5 Well-Known Member

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    Re: Exim Email Problem: 450 4.7.1 Client host rejected: cannot find your reverse host

    I didn´t see any issue, what issue did you find? i have others server that appears as yeallow equal my domain, and there is no problem.
     
  6. Infopro

    Infopro cPanel Sr. Product Evangelist
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    Re: Exim Email Problem: 450 4.7.1 Client host rejected: cannot find your reverse host

    Any warning should be looked into.
     
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  7. cPanelTristan

    cPanelTristan Quality Assurance Analyst
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    Re: Exim Email Problem: 450 4.7.1 Client host rejected: cannot find your reverse host

    Can you please provide the full error message you are getting that includes what IP and hostname it believes isn't resolving properly?

    The icnetwork.com.br domain's IP of 186.251.87.30 does return a PTR of br01.icnetwork.com.br which is the port 25 telnet response for the IP as well, so I don't see where there isn't an rDNS functioning.
     
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  8. m0rpheu5

    m0rpheu5 Well-Known Member

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    Re: Exim Email Problem: 450 4.7.1 Client host rejected: cannot find your reverse host

    Ok, follow below two emails that i´m getting error to send emails.

    delivering 1Qjs98-0000zQ-0H
    Connecting to mx.a.locaweb.com.br [186.202.4.42]:25 ... connected
    SMTP<< 450 4.7.1 Client host rejected: cannot find your reverse hostname, [186.251.87.30]
    SMTP>> QUIT
    LOG: MAIN
    SMTP error from remote mail server after initial connection: host mx.a.locaweb.com.br [186.202.4.42]: 450 4.7.1 Client host rejected: cannot find your reverse hostname, [186.251.87.30]
    LOG: MAIN
    == financeiro@higiemix.com.br R=dk_lookuphost T=dk_remote_smtp defer (0): SMTP error from remote mail server after initial connection: host mx.a.locaweb.com.br [186.202.4.42]: 450 4.7.1 Client host rejected: cannot find your reverse hostname, [186.251.87.30]

    ----------------------------------------------------------------------------------------------------------

    delivering 1QjrYt-0007tN-Nr
    Connecting to mx.a.locaweb.com.br [186.202.4.42]:25 ... connected
    SMTP<< 450 4.7.1 Client host rejected: cannot find your reverse hostname, [186.251.87.30]
    SMTP>> QUIT
    LOG: MAIN
    SMTP error from remote mail server after initial connection: host mx.a.locaweb.com.br [186.202.4.42]: 450 4.7.1 Client host rejected: cannot find your reverse hostname, [186.251.87.30]
    LOG: MAIN
    == financeiro@logosst.com.br R=dk_lookuphost T=dk_remote_smtp defer (0): SMTP error from remote mail server after initial connection: host mx.a.locaweb.com.br [186.202.4.42]: 450 4.7.1 Client host rejected: cannot find your reverse hostname, [186.251.87.30]

    Thanks.
     
  9. cPanelTristan

    cPanelTristan Quality Assurance Analyst
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    Re: Exim Email Problem: 450 4.7.1 Client host rejected: cannot find your reverse host

    I think you are going to have to contact whoever runs 186.202.4.42 to ask them to check their resolver. 186.251.87.30 does have an rDNS entry, so their resolver isn't accurate at all in that message:

    Code:
    $ dig -x 186.251.87.30 +short
    br01.icnetwork.com.br.
     
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