cat /etc/os-release
NAME="CentOS Linux"
VERSION="8 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="8"
PLATFORM_ID="platform:el8"
PRETTY_NAME="CentOS Linux 8 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:8"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"

CENTOS_MANTISBT_PROJECT="CentOS-8"
CENTOS_MANTISBT_PROJECT_VERSION="8"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="8"

for my $port (@ports) {
   #$conn{$port} = $ctx->socket(ZMQ_DEALER);
   $conn{$port} = $ctx->socket(ZMQ_REQ);
    $conn{$port}->die_on_error(1);
   $conn{$port}->connect("tcp://127.0.0.1:$port");
   print $conn{$port}->has_error() . $conn{$port}->last_errno() . "\n";
}

./script/perl ../scripts/zeromq-client.pl 
00
00
00
00
00
00
00
00
00
00
00
pushing to: 42002
pushing to: 42021
pushing to: 42023
pushing to: 62111
pushing to: 42006
pushing to: 42022
pushing to: 42003
pushing to: 42008
pushing to: 42007
pushing to: 42004
pushing to: 42005
got reply 'job is finished 42022 sleep 0' from 42022
got reply 'job is finished 42007 sleep 0' from 42007
got reply 'job is finished 42021 sleep 1' from 42021
got reply 'job is finished 42005 sleep 1' from 42005
got reply 'job is finished 42023 sleep 2' from 42023
got reply 'job is finished 42004 sleep 3' from 42004
got reply 'job is finished 42008 sleep 4' from 42008