Yesterday I installed spamassassin package on a server running RHEL 6.8. Then this morning, I received an email alert with the following message:

This seems to be a bug exists in an old version of IO::Socket::INET6. Upgrading this package should fix the problem:

Ref: http://stackoverflow.com/questions/23909848/perl-iosocketinet6sockaddr-in6-redefined-error