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DKIM with Postfix
Jika web-server / webapp anda punya masalah delivery, DKIM (DomainKeys Identified Mail) kemungkinan akan bisa menolong.


If mails from your web-server/webapp is having delivery issues, DKIM (DomainKeys Identified Mail) can help you big time.
Sangat di sarankan untuk menggunakan DKIM untuk outgong email meskipun server kita tidak menjalankan mail hosting sama sekali.
 
Its highly recommended to use DKIM for outgoing emails even if your server is not running any kind of mail-hosting.


==Install DKIM==
==Install DKIM==
Line 15: Line 13:
==DKIM config==
==DKIM config==


Open dkim config file vim /etc/opendkim.conf
Edit
 
vi /etc/opendkim.conf
 
Tambahkan (mis. untuk domain example.com domain/subdomain)


Add following lines towards end. Make sure you replace example.com with your domain/subdomain.
Domain                  example.com
KeyFile                /etc/postfix/dkim.key
Selector                mail
# SOCKET                  inet:8891@localhost


Domain                  example.com
Edit
KeyFile                /etc/postfix/dkim.key
Selector                mail
SOCKET                  inet:8891@localhost


Next open dkim defaults file vim /etc/default/opendkim
vi /etc/default/opendkim


Change default socket path by adding a line like below:
SOCKET="inet:8891@localhost"


SOCKET="inet:8891@localhost"
==Postfix konfigurasi==


Postfix file
Edit


Open postfix main config file vim /etc/postfix/main.cf
vi /etc/postfix/main.cf


Add following lines towards end.
Tambahkan


# DKIM
# DKIM
milter_default_action = accept
milter_default_action = accept
milter_protocol = 2
milter_protocol = 2
smtpd_milters = inet:localhost:8891
smtpd_milters = inet:localhost:8891
non_smtpd_milters = inet:localhost:8891
non_smtpd_milters = inet:localhost:8891


DKIM Key Generation
==DKIM Key Generation==


Run following commands with mail and example.com matching values used in /etc/opendkim.conf file in earlier step.
Jalankan perintah berikut dengan mail dan example.com matching dengan yang digunakan /etc/opendkim.conf  


opendkim-genkey -t -s mail -d example.com
opendkim-genkey -t -s mail -d example.com


This command will generate mail.private and mail.txt file. mail.private is private key that will be used to sign outgoing emails. Move it to the location we specified earlier in /etc/opendkim.conf
Akan keluar 2 file mail.private dan mail.txt.
mail.private adalah private key yang digunakanakan untuk sign outgoing email. Pindahkan ke lokasi yang di set di /etc/opendkim.conf


cp mail.private /etc/postfix/dkim.key
cp mail.private /etc/postfix/dkim.key


DNS Record Setup
==DNS Record Setup==


Next, you need to create a TXT record on DNS end. Just check content of mail.txt file created by opendkim-genkey command we ran above.
Buat TXT record di DNS. Isinya ada di mail.txt, coba lihat menggunakan


cat mail.txt
cat mail.txt


You will see something like below:
Isinya kira-kira,


mail._domainkey IN TXT "v=DKIM1; k=rsa; t=y; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDYv84GSl0Xp2CrPdFqMZ9ShBDi9Pal9XpfIf7asEENxLRdIka3TONpqtrcCKksROJBNh2G3OVGuoGJ1watQGT46B+zQtjcCI67+WiTlb2D98s1UV3KO7oi/0QH/lH8DzUmrGJUIy3ZBQ9mIu1t6YDyi8y3hlhTILHW7G4HV/VtwQIDAQAB" ; ----- DKIM key mail for example.com
mail._domainkey IN TXT "v=DKIM1; k=rsa; t=y; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDYv84GSl0Xp2CrPdFqMZ9ShBDi9Pal9XpfIf7asEENxLRdIka3TONpqtrcCKksROJBNh2G3OVGuoGJ1watQGT46B+zQtjcCI67+WiTlb2D98s1UV3KO7oi/0QH/lH8DzUmrGJUIy3ZBQ9mIu1t6YDyi8y3hlhTILHW7G4HV/VtwQIDAQAB" ; ----- DKIM key mail for example.com


TXT record will require NAMS & VALUE.
TXT ini membutuhkan NAME & VALUE.


Use mail._domainkey for NAME and long string in quotes starting from v=DKIM1 as VALUE.
Gunakan mail._domainkey untuk NAME dan long string yang dimulai dari v=DKIM1 as VALUE.


Below is a sample screenshot for a TXT record. User-interface on your end might differ.
Below is a sample screenshot for a TXT record. User-interface on your end might differ.


TXT-DKIM record-1
==Start Signing==
 
If you are editing a previous DNS record, it might take sometime for changes to propogate.
Start Signing


Once al config & setup done, you need to start DKIM service and restart postfix.
Start DKIM dan Postfix


service opendkim start
service opendkim start
service postfix restart
service postfix restart


Testing DKIM setup for correctness
==Testing DKIM setup for correctness==


Anything we do, specially for first time, must end with successful testing!
Anything we do, specially for first time, must end with successful testing!


There are many tools for testing. I will mention few of them below.
There are many tools for testing. I will mention few of them below.
Verify DNS Records for DKIM Setup
 
==Verify DNS Records for DKIM Setup==


This will ONLY verify if your TXT record is created successfully.
This will ONLY verify if your TXT record is created successfully.
Line 90: Line 91:
Classic and easy. You must be having this already. Running…
Classic and easy. You must be having this already. Running…


dig mail._domainkey.example.com TXT
dig mail._domainkey.example.com TXT


should return a response like…
should return a response like…


;; ANSWER SECTION:
;; ANSWER SECTION:
mail._domainkey.exmaple.com. 86400 IN TXT "v=DKIM1\;" "k=rsa\;" "t=y\;" "p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDYv84GSl0Xp2CrPdFqMZ9ShBDi9Pal9XpfIf7asEENxLRdIka3TONpqtrcCKksROJBNh2G3OVGuoGJ1watQGT46B+zQtjcCI67+WiTlb2D98s1UV3KO7oi/0QH/lH8DzUmrGJUIy3ZBQ9mIu1t6YDyi8y3hlhTILHW7G4HV/VtwQIDAQAB"
mail._domainkey.exmaple.com. 86400 IN TXT "v=DKIM1\;" "k=rsa\;" "t=y\;" "p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDYv84GSl0Xp2CrPdFqMZ9ShBDi9Pal9XpfIf7asEENxLRdIka3TONpqtrcCKksROJBNh2G3OVGuoGJ1watQGT46B+zQtjcCI67+WiTlb2D98s1UV3KO7oi/0QH/lH8DzUmrGJUIy3ZBQ9mIu1t6YDyi8y3hlhTILHW7G4HV/VtwQIDAQAB"


Web-based Record Check
==Web-based Record Check==


You can use http://www.protodave.com/tools/dkim-key-checker/
You can use http://www.protodave.com/tools/dkim-key-checker/


Use selector  mail and domain example.com there.
Use selector  mail and domain example.com there.
Verify DKIM Signing
 
Test #1 – Email-based
==Verify DKIM Signing==
 
==Test #1 – Email-based==


If you have setup keys correctly then you should pass this test.
If you have setup keys correctly then you should pass this test.
Line 111: Line 114:
It’s better to use swaks tools for mail-testing (apt-get install swaks).
It’s better to use swaks tools for mail-testing (apt-get install swaks).


swaks -t check-auth2@verifier.port25.com -f me@example.com
swaks -t check-auth2@verifier.port25.com -f me@example.com


Replace me@example.com with your mail id where you would like to receive test results.
Replace me@example.com with your mail id where you would like to receive test results.
Test #2 – Web-based
 
==Test #2 – Web-based==


Better choice will be to use a service like http://www.mail-tester.com/  which gives you a temporary email ID and web-interface to see what happens to the email on receiving end!
Better choice will be to use a service like http://www.mail-tester.com/  which gives you a temporary email ID and web-interface to see what happens to the email on receiving end!

Revision as of 02:27, 4 October 2019

Sumber: https://easyengine.io/tutorials/mail/dkim-postfix-ubuntu/


Jika web-server / webapp anda punya masalah delivery, DKIM (DomainKeys Identified Mail) kemungkinan akan bisa menolong.

Sangat di sarankan untuk menggunakan DKIM untuk outgong email meskipun server kita tidak menjalankan mail hosting sama sekali.

Install DKIM

apt-get install opendkim opendkim-tools


DKIM config

Edit 

vi /etc/opendkim.conf

Tambahkan (mis. untuk domain example.com domain/subdomain) 

Domain                  example.com
KeyFile                 /etc/postfix/dkim.key
Selector                mail
# SOCKET                  inet:8891@localhost

Edit 

vi /etc/default/opendkim

SOCKET="inet:8891@localhost"

Postfix konfigurasi

Edit 

vi /etc/postfix/main.cf

Tambahkan 

# DKIM
milter_default_action = accept
milter_protocol = 2
smtpd_milters = inet:localhost:8891
non_smtpd_milters = inet:localhost:8891

DKIM Key Generation

Jalankan perintah berikut dengan mail dan example.com matching dengan yang digunakan /etc/opendkim.conf 

opendkim-genkey -t -s mail -d example.com

Akan keluar 2 file mail.private dan mail.txt. mail.private adalah private key yang digunakanakan untuk sign outgoing email. Pindahkan ke lokasi yang di set di /etc/opendkim.conf 

cp mail.private /etc/postfix/dkim.key

DNS Record Setup

Buat TXT record di DNS. Isinya ada di mail.txt, coba lihat menggunakan 

cat mail.txt

Isinya kira-kira, 

mail._domainkey IN TXT "v=DKIM1; k=rsa; t=y;  p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDYv84GSl0Xp2CrPdFqMZ9ShBDi9Pal9XpfIf7asEENxLRdIka3TONpqtrcCKksROJBNh2G3OVGuoGJ1watQGT46B+zQtjcCI67+WiTlb2D98s1UV3KO7oi/0QH/lH8DzUmrGJUIy3ZBQ9mIu1t6YDyi8y3hlhTILHW7G4HV/VtwQIDAQAB" ; ----- DKIM key mail for example.com

TXT ini membutuhkan NAME & VALUE.

Gunakan mail._domainkey untuk NAME dan long string yang dimulai dari v=DKIM1 as VALUE.

Below is a sample screenshot for a TXT record. User-interface on your end might differ.

Start Signing

Start DKIM dan Postfix 

service opendkim start
service postfix restart

Testing DKIM setup for correctness

Anything we do, specially for first time, must end with successful testing!

There are many tools for testing. I will mention few of them below.

Verify DNS Records for DKIM Setup

This will ONLY verify if your TXT record is created successfully. dig command

Classic and easy. You must be having this already. Running… 

dig mail._domainkey.example.com TXT

should return a response like… 

;; ANSWER SECTION:
mail._domainkey.exmaple.com. 86400 IN	TXT	"v=DKIM1\;" "k=rsa\;" "t=y\;"  "p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDYv84GSl0Xp2CrPdFqMZ9ShBDi9Pal9XpfIf7asEENxLRdIka3TONpqtrcCKksROJBNh2G3OVGuoGJ1watQGT46B+zQtjcCI67+WiTlb2D98s1UV3KO7oi/0QH/lH8DzUmrGJUIy3ZBQ9mIu1t6YDyi8y3hlhTILHW7G4HV/VtwQIDAQAB"

Web-based Record Check

You can use http://www.protodave.com/tools/dkim-key-checker/

Use selector mail and domain example.com there.

Verify DKIM Signing

Test #1 – Email-based

If you have setup keys correctly then you should pass this test.

You can test by simply sending an email to autorespond+dkim@dk.elandsys.com or check-auth2@verifier.port25.com

It’s better to use swaks tools for mail-testing (apt-get install swaks). 

swaks -t check-auth2@verifier.port25.com -f me@example.com

Replace me@example.com with your mail id where you would like to receive test results.

Test #2 – Web-based

Better choice will be to use a service like http://www.mail-tester.com/ which gives you a temporary email ID and web-interface to see what happens to the email on receiving end!



Referensi

Pranala Menarik

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