Webmail and reverse lookup

rsutc

• December 29, 2017 12:34

Recently, to foil a spammer who was spoofing a return address on our server, I enabled reverse PTR lookup. However, this killed Webmail. A user could sent a message through the box using a mail client, but any attempt by a user to send one through Webmail was forbidden by administrative policy. A search of the exit logs showed that the attempt to send was being foiled by a reverse lookup failure on the sender by our own box! Yet, I had disabled spam checks on outgoing mail. So...what is the problem here and how do I address it. I don't want to leave reverse lookup disabled. And yet..it cannot truly function for all domains because many share a single IP.

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  rsutc

  • December 29, 2017 17:35

  That should be exim logs. Mumble mumble spell checker.

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  cPanelMichael

  • December 30, 2017 15:53

  enabled reverse PTR lookup.

  
  Hello, Could you confirm the specific option you enabled and how you enabled it? Thank you.

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  rsutc

  • January 01, 2018 16:11

  In the section of the advanced EXIM config: custom_begin_check_message_pre I put: require verify = reverse_host_lookup message = Your mail server IP address ($sender_host_address) has no reverse DNS PTR This has worked in the past, but this time Webmail could not work. Rick

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  cPanelMichael

  • January 03, 2018 17:13

  Hello, Are you able to reproduce this issue with all three webmail applications, or is it isolated to a single one? Note the information on the following thread: Prevention client IP to appear in mail headers Horde webmail Thank you.

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