Configuring Zimbra 8.x to use DKIM Authentication
Example for ‘mydomain.com’
ssh root@zimbra.mydomain.com
su - zimbra
Creating the DKIM keys for a domain:
/opt/zimbra/libexec/zmdkimkeyutil -a -d mydomain.com
Example of result:
50F0EEFE-AB8C-11E2-B7AE-FC2CE654A0ED._domainkey IN TXT ( "v=DKIM1; k=rsa; "
"p=MIGfMA0GCSqGSIb3DQEBAQUCA4GNADCBiQKBgQDodIcoFWJsfsSzsdINY/ZiOKn3qKLt+qmEl1cDYApi0PCHwQmqTl9mhRKs3obfgN8O9nT227CDg9NI7MMu8r0fOatQRQ1YHesDmHIo1lELioDNd5QZPg1AUum0CPsDuR+YI5AG5wZhZ4c3ei0Uv3cu4aTIhGrRgnD081sysJ5vZwIDAQAB" ) ; ----- DKIM key 50F0EEFE-AB8C-11E2-B7AE-FC2CE654A0ED for mydomain.com
IMPORTANT: Enter the above result as TXT field in the DNS of example.com domain.
Testing the DKIM keys:
Command syntax:
/opt/zimbra/opendkim/sbin/opendkim-testkey -d example.com -s 0E9F184A-9577-11E1-AD0E-2A2FBBAC6BCB -x /opt/zimbra/conf/opendkim.conf
-d is the domain name (example.com)
-s is the selector name (0E9F184A-9577-11E1-AD0E-2A2FBBAC6BCB…value entered in first field of TXT record)
-x is the configuration file (/opt/zimbra/conf/opendkim.conf)
Example of DNS TXT record:
0E9F184A-9577-11E1-AD0E-2A2FBBAC6BCB._domainkey IN TXT "v=DKIM1; k=rsa; " "p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC2R............."
Example of key test command:
/opt/zimbra/opendkim/sbin/opendkim-testkey -d example.com -s 0E9F184A-9577-11E1-AD0E-2A2FBBAC6BCB -x /opt/zimbra/conf/opendkim.conf
– If no result is shown: then the Key is correct.
– If something is wrong then the following similar message would show up:
opendkim-testkey: '0E9F184A-9577-11E1-AD0E-2A2FBBAC6BCB._domainkey.example.com' record not found
Retrieving a DKIM key from Zimbra:
/opt/zimbra/libexec/zmdkimkeyutil -q -d example.com
Deleting a DKIM key from Zimbra
/opt/zimbra/libexec/zmdkimkeyutil -r -d example.com
Example of a mail headers sent using DKIM and SPF Authentication
Received: from zimbra.example.com ([84.200.75.211])
by mx.google.com with ESMTPS id fv8si9645396bkc.151.2013.04.22.14.24.39
(version=TLSv1.2 cipher=ECDHE-RSA-RC4-SHA bits=128/128);
Mon, 22 Apr 2013 14:24:39 -0700 (PDT)
Received-SPF: pass (google.com: domain of michel@example.com designates 84.200.75.211 as permitted sender) client-ip=84.200.75.211;
Authentication-Results: mx.google.com;
spf=pass (google.com: domain of michel@example.com designates 84.200.75.211 as permitted sender) smtp.mail=michel@example.com;
dkim=pass header.i=@example.com
DKIM-Filter: OpenDKIM Filter v2.7.1 zimbra.example.com 37BCE8CAFC
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=example.com;
s=50F0EEFE-AB8C-11E2-B7AE-FC2CE654A0ED; t=1366665881;
bh=vJ74cUsPMKlw/MROSXLmZbSV7uGHNQFAGzPZcMjnQPU=;
h=Date:From:To:Message-ID:Subject:MIME-Version:Content-Type;
b=w6XTCY+nnfc/jZCtfA4QO7yIMLX9P6Bzlm+r5BGUUwdFTDtLb0CmrE8eYi+8mLDuR
M3wrGuOfo5U239h4ixp6nnc1Ogj5xb3uIfe9xVOQaXBeIz7yKDFWBiUaMT7FQEqpgU
aGBJ96p8bsxwyuU1L3/uSdyyykHPUapGNoTpH/R0=