Work around below
[base] name=CentOS-$releasever - Base #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&rep...
baseurl=http://ftp.hostrino.com/pub/centos/$releasever/os/$basearch/ gpgcheck=1 gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos4 exclude=php* httpd* postgres* MySQL* mysql* perl perl-DBD-MySQL perl-DBD-Pg perl-DBI perl-suidperl unixODBC* mod_auth_mysql mod_auth_pgsql mod_perl mod_perl-devel mod_ssl priority=1
#released updates [update] name=CentOS-$releasever - Updates #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&rep...
baseurl=http://ftp.hostrino.com/pub/centos/$releasever/updates/$basearch/ gpgcheck=1 gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos4 exclude=php* httpd* postgres* MySQL* mysql* perl perl-DBD-MySQL perl-DBD-Pg perl-DBI perl-suidperl unixODBC* mod_auth_mysql mod_auth_pgsql mod_perl mod_perl-devel mod_ssl priority=1
I tried changing perl to perl-* and yum check-update finally listed the perl package.
yum check-update 18 packages excluded due to repository priority protections
httpd.x86_64 2.0.59-1.el4s1.10.el4. centosplus httpd-manual.x86_64 2.0.59-1.el4s1.10.el4. centosplus mod_perl.x86_64 2.0.3-1.el4s1.3 centosplus mod_ssl.x86_64 1:2.0.59-1.el4s1.10.el centosplus mysql.x86_64 5.0.54-1.el4.centos centosplus mysql-devel.x86_64 5.0.54-1.el4.centos centosplus mysql-server.x86_64 5.0.54-1.el4.centos centosplus mysqlclient10.x86_64 3.23.58-9.2.c4 centosplus perl.x86_64 4:5.8.8-5.el4s1_2 centosplus perl-DBD-MySQL.x86_64 3.0008-1.el4.centos centosplus perl-DBD-Pg.x86_64 1.49-1.el4s1 centosplus perl-DBI.x86_64 1.54-1.el4s1 centosplus perl-libwww-perl.noarch 5.805-1.1.1 centosplus php.x86_64 5.1.6-3.el4s1.8 centosplus php-gd.x86_64 5.1.6-3.el4s1.8 centosplus php-ldap.x86_64 5.1.6-3.el4s1.8 centosplus php-mbstring.x86_64 5.1.6-3.el4s1.8 centosplus php-pear.noarch 1:1.4.11-1.el4s1.1 centosplus php-pgsql.x86_64 5.1.6-3.el4s1.8 centosplus postgresql.x86_64 8.1.9-1.el4s1.1 centosplus postgresql-devel.x86_64 8.1.9-1.el4s1.1 centosplus postgresql-libs.x86_64 8.1.9-1.el4s1.1 centosplus postgresql-server.x86_64 8.1.9-1.el4s1.1 centosplus unixODBC.x86_64 2.2.12-1.el4s1.1 centosplus