In some cases, users of Imunify360 v4.7 can experience issues with IMAP authorization performance. These issues are related to the amount of UDP traffic produced when Imunify360 protects a server against brute force mail attacks.
The issue can be identified by the presence of mass entries similar to this one in /var/log/messages:
Mar 4 20:36:03 jump05 pam_imunify_daemon: 2020/03/04 20:36:03 RBL check: lookup 99.71.43.95.net-brute.rbl.imunify.com. on 79.98.109.15:53: dial udp: i/o timeout
Imunify360 version 4.8 contains the necessary fixes and is already available for update. However, the automatic rollout may take up to nine days. 100% production rollout is expected on Jun 10, 2020.
To mitigate issue in the meantime, we recommend making the following changes in the /etc/pam_imunify/i360.ini file:
RBL_timeout=3RBL_nameserver=mydns.com:53# systemctl restart imunify360-pam
If you don’t want to wait until the rollout process is complete, and you wish to upgrade to Imunify360 version 4.8 immediately, run the following commands:
# wget https://repo.imunify360.cloudlinux.com/defence360/imunify-force-update.sh
# bash imunify-force-update.sh