Zimbra - DoS attack, fail2ban and analyze logs.

I'd like to provide you complex solution how to fight with attack and predict them. I implemented fail2ban and integrated DoS filter of Zimbra to defeat of attack on the mail server. Client's server was attacked, and one email account was hacked. Hackers sent a lot of email 2 days. The server was added to blacklists and client had email from ISP provider that it has complaint from other clients and solve urgent the issue the spam from your server.

So, I will give you some advice how to avoid such situation and how to set your server from attack.

After installation Hyper-V role on the Windows Server it reboots cycling.

If you face the issue - after installation Hyper-V role on the Windows Server it reboots cycling, you need to try advice below.

I faced with it on server HP DL380p Gen 8 with OS Windows Server 2019.

How to increase disk size in Zimbra on virtual machine

If you face the issue with free space on our disk in Zimbra and decide to increase the size, I propose you to consider two scenarios: 

First - You have less than 4 partitions in your virtual disk, like below and you need to extend the disk.

Disk /dev/sda:

   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *        2048     2099199     1048576   83  Linux

/dev/sda2         2099200   419430399   208665600   8e  Linux LVM

/dev/sda3       419430400   629145599   104857600   8e  Linux LVM

Second - You have 4 partitions in your virtual disk,

Disk /dev/sda:  

   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *        2048     2099199     1048576   83  Linux

/dev/sda2         2099200   419430399   208665600   8e  Linux LVM

/dev/sda3       419430400   629145599   104857600   8e  Linux LVM

/dev/sda4       629145600   671088639    20971520   8e  Linux LVM

squid - The ssl_crtd helpers are crashing too rapidly or ERROR: loading file /usr/local/etc/squid/errors/en/ No such file or directory

 If you faced issues on squid in Pfsence like below and squid terminated abnormally:

1) squid - The ssl_crtd helpers are crashing too rapidly

2)  ERROR: loading file /usr/local/etc/squid/errors/en/error-details.txt': (2) No such file or directory Unable to load default error language files. Reset to backups.

You should do the next steps:

Мониторинг устройства через zabbix агента на удаленном сервере.

Необходимо настроить мониторинг компьютера в сети через ping, но так чтобы ping шел от сервера в той же сети, а не от zabbix сервера.