dcc-nagios from server:mail project

For 15.7 run the following as root:

zypper addrepo https://download.opensuse.org/repositories/server:mail/15.7/server:mail.repo
zypper refresh
zypper install dcc-nagios

For 15.6 run the following as root:

zypper addrepo https://download.opensuse.org/repositories/server:mail/15.6/server:mail.repo
zypper refresh
zypper install dcc-nagios

For SLE 12 SP5 run the following as root:

zypper addrepo https://download.opensuse.org/repositories/server:mail/SLE_12_SP5/server:mail.repo
zypper refresh
zypper install dcc-nagios