opendkim-testkey returns "invalid data set type", while if I specify domain and selector I got "Key OK"

Question

I'm having the problem that opendkim testkey returns error "invalid data set type" unless I pass the domain and the selector to the command. Why does it happen? Details below:

Without domain and selector:

root@condor1796 /etc/opendkim # sudo -u opendkim opendkim-testkey -vvvv
opendkim-testkey: using default configfile /etc/opendkim.conf
opendkim-testkey: invalid data set type
root@condor1796 /etc/opendkim # 

with the domain and the selector specified:

root@condor1796 /etc/opendkim # sudo -u opendkim opendkim-testkey -vvvv -d numbeo.com -s mail
opendkim-testkey: using default configfile /etc/opendkim.conf
opendkim-testkey: checking key 'mail._domainkey.numbeo.com'
opendkim-testkey: key not secure
opendkim-testkey: key OK

Key not secure output is, as I've learned in another thread:

The "key not secure" does not indicate an error. It is an expected consequence of not using DNSSSEC.

This is my config file:

root@condor1796 /etc/opendkim # cat /etc/opendkim.conf
OversignHeaders     From
TrustAnchorFile       /usr/share/dns/root.key

AutoRestart             Yes
AutoRestartRate         10/1h
UMask                   002
Syslog                  yes
SyslogSuccess           Yes
LogWhy                  Yes

Canonicalization        relaxed/simple

ExternalIgnoreList      refile:/etc/opendkim/TrustedHosts
InternalHosts           refile:/etc/opendkim/TrustedHosts
KeyTable                refile:/etc/opendkim/KeyTable
SigningTable            refile:/etc/opendkim/SigningTable

Mode                    sv
PidFile                 /var/run/opendkim/opendkim.pid
SignatureAlgorithm      rsa-sha256

UserID                  opendkim:opendkim

Socket                  inet:12301@localhost

And these are referenced files:

root@condor1796 /etc # sudo -u opendkim cat /etc/opendkim/KeyTable
mail._domainkey.numbeo.com numbeo.com:mail:/etc/opendkim/keys/numbeo.com/mail.private
root@condor1796 /etc # sudo -u opendkim head -n 2 /etc/opendkim/keys/numbeo.com/mail.private
-----BEGIN RSA PRIVATE KEY-----
MIICXgIBAAKBgQDPqBmXSBbSXdmDIOqriDqI7/HJz1AqJNjK+Jqd0EQHEmXS5BHB
root@condor1796 /etc # sudo -u opendkim cat /etc/opendkim/SigningTable 
*@numbeo.com mail._domainkey.numbeo.com

Any idea why I'm getting error with opendkim-testkey if I don't specify the domain and the selector?

Answer 1

I've solved the problem. This thread helped:

OpenDKIM not signing mail

opendkim.conf has to have this line

KeyTable                /etc/opendkim/KeyTable

(without refile:/ prefix)

This now works:

root@condor1796 /etc # sudo -u opendkim opendkim-testkey -vvvv 
opendkim-testkey: using default configfile /etc/opendkim.conf
opendkim-testkey: record 0 for 'numbeo.com' retrieved
opendkim-testkey: checking key 'numbeo.com'
opendkim-testkey: key numbeo.com: OK
opendkim-testkey: key numbeo.com not secure
opendkim-testkey: 1 key checked; 1 pass, 0 fail