[ERROR] Error in accept: Too many open files 1

With some versions of MariaDB, the server could stop responding to sql queries. service mysql status shows mysql[413]: ERROR 23 (HY000) at line 1: Out of resources when opening file ‘./…’ (Errcode: 24 “Too many open files”) [ERROR] Error in accept: Too many open files To adjust the limits of […]

The following packages have unmet dependencies

Sometimes an installation fails due to inappropriate dependencies. This is usually due to additional repos. This can be remedied by downgrading the not matching packet. As an example here the output of apt-get install openssl-dev: libssl-dev : Depends: libssl1.0.0 (= 1.0.1t-1+deb8u5) but 1.0.2j-1~bpo8+1 is to be installed Recommends: libssl-doc but […]

Hetzner – copy IPv6 Reverse-DNS

You can continue to use the old IPv4 subnet with a new server at Hetzner. With IPv6, it does not work unfortunately. Although I do not understand why I can keep all IPv4 (subnet and / or single), but not the IPv6 addresses. It’s annoying when you have to change […]

ISPConfig: replace apache with nginx 11

In this tutorial i show you how to replace apache with nginx using ISPConfig I performed the migration for serveral sites running Joomla 2.x, Joomla 3.x, WordPress and some static / self-written pages. The server runs ISPConfig installed using the Perfect Server Howto from howtoforge.com. There are some […]

mysql-replication – Could not parse relay log event entry

When mysql shows Slave_IO_Running and Slave_SQL_Running is false, then there is much evidence that the current slave relay log is broken. show slave status \G then looks for example like this: mysql> show slave status \G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: master.example.com Master_User: […]

How to send emails properly

To send emails with Postfix, a few things have to be considered. These are either defined in RFCs or generally useful. 1. matching reverse DNS RFC1912 requires that the PTR record and the A record in DNS match. On the one hand it shows that the administrator understands the RFCs, […]

force apt-get to use ipv4

Debian / Ubuntu prefer to use IPv6 DNS Records. This leads to problems if the server supports only IPv4. The problem can easily solved. We only need to change the config for getaddrinfo(). Open /etc/gai.conf and change #precedence ::ffff:0:0/96 100 to precedence ::ffff:0:0/96 100 For me it was line 54.