Exim Localhost Vs 127.0.0.1

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Hi all,

I had a big problem I did not figured out. It is solved, but I have questions about the matter.

It’s about Exim 4.72/CentOS 6.

Connecting to Exim via “localhost” is denies relay Connecting to Exim via 127.0.0.1 accepts the relay
“localhost” is in the local_domains domainlists
“localhost” is resolving to 127.0.0.1 in /etc/hosts

Why?

[mihamina@recette53 ~]$ rpm -aq | grep exim exim-4.72-4.el6.x86_64

[mihamina@recette53 ~]$ telnet localhost 25
Trying ::1… Connected to localhost. Escape character is ‘^]’.
220 recette53.ideoneov.com ESMTP Exim 4.72 Mon, 11 Mar 2013 10:09:27 +0100
HELO mihamina
250 recette53.ideoneov.com Hello localhost [::1]
MAIL from:
250 OK
RCPT to:
550 relay not permitted

mihamina@recette53 ~]$ telnet 127.0.0.1 25
Trying 127.0.0.1… Connected to 127.0.0.1. Escape character is ‘^]’.
220 recette53.ideoneov.com ESMTP Exim 4.72 Mon, 11 Mar 2013 10:10:26 +0100
HELO mihamina
250 recette53.ideoneov.com Hello localhost [127.0.0.1]
MAIL from:
250 OK
RCPT to:
250 Accepted DATA
354 Enter message, ending with “.” on a line by itself From:
To:
Subject: Haftra Andrana

Ity dia andrana fotsiny ihany.
.
250 OK id=1UEykk-0006Fr-TO
QUIT
221 recette53.ideoneov.com closing connection

One thought on - Exim Localhost Vs 127.0.0.1

  • Hi Mihamina,

    I’m not a specialist on EXIM, but obviously your system resolves ‘localhost’ to the IPv6 address ::1.

    Probably you have allowed EXIM to relay for 127.0.0.1/8, but not for ::1, so it will allow relay access on IPv4 localhost, but not on IPv6 localhost.

    Cheers,

    Peter.

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