After plesk dkim activation any services (like opendkim) not required. The keys store in «/etc/domainkeys/», but public dkim keys do not store.
We can easily generate them:
# openssl rsa -in /etc/domainkeys/somedomain.tld/default -pubout -out /etc/domainkeys/somedomain.tld/public
# writing RSA key
After that you will see:
# cat /etc/domainkeys/somedomain.tld/public
-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDNP/0esApEWVmQEtjbT8WGJSyPhKpNvxuxHDSf/TChc1ssgO+DWtXOdFyd/jM1L+vtBUOXLewmrWJ+shnAiZOibyR2LtCvmBZ44K08UvC6Xqnz8Jh9BLv9K0KZ/3tX7UU0DMHQ/zWb1Ya6cWHfkfJc4H+DkqAGQhQPZMk3nrwXVwIDAQAB
-----END PUBLIC KEY-----
And than you can set up it in you dns hosting provider, like: name:
default._domainkey
type:
TXT
value:
"k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDNP/0esApEWVmQEtjbT8WGJSyPhKpNvxuxHDSf/TChc1ssgO+DWtXOdFyd/jM1L+vtBUOXLewmrWJ+shnAiZOibyR2LtCvmBZ44K08UvC6Xqnz8Jh9BLv9K0KZ/3tX7UU0DMHQ/zWb1Ya6cWHfkfJc4H+DkqAGQhQPZMk3nrwXVwIDAQAB"
For dkim testing you can use this service.