DNS cache

DNS Cache on VAPP

Oplon ADC does not make DNS requests on its own, but configurations can be set up that indirectly generate many DNS requests. One such case is the use of machine names and not addresses such as emdpoint. This configuration is absolutely legitimate and creates additional flexibility in configuration, but in the presence of consumer firewalls or low-quality equipment it can cause problems within the datacenters.

In case we're in this situation, no problem, you can run DNS caches within the Virtual Appliances in a few moments.

DNSMasq installation and setup

Installing dnsmasq on virtual appliances is very simple and depending on the CentOS or Debian derivation deployment (e.g. RedHAT or Ubuntu) the action is as follows:

CentOS derivation

yum --y install dnsmasq

Debian derivation

apt-get install dnsmasq

Once installed, perform the following root steps for configuration:

1) Edit /etc/dnsmasq.conf

vi /etc/dnsmasq.conf

2) In /etc/dnsmasw.conf Change the following parameter from

#bogus-priv

a

bogus-priv

3) Allocate the following directory

mkdir -p /var/log/dnsmasq

4) Upload the following configuration to a new /etc/dnsmasq.d/lbl.conf file with the following values

log-facility : /var/log/dnsmasq/dnsmasq.log
log-async - 15
clear-on-reload

5) Name resolution change

Change the name resolution through the network manager (nmtui) or through the /etc/resolv.conf file where the network manager is not present by putting localhost in the first position:

nameserver 127.0.0.1
nameserver 8.8.8.8 <- This is an example, to give you your DNS name

6) Enabling the service

systemctl enable dnsmasq
systemctl start dnsmasq
systemctl status dnsmasq
 dnsmasq.service - DNS caching server.
   Loaded: loaded (/usr/lib/systemd/system/dnsmasq.service; enabled; vendor preset: disabled)
   Active: active (running) since Wed XXXXXXXXXXXX
 Main PID: 39771 (dnsmasq)
   CGroup: /system.slice/dnsmasq.service
        |__ 39771 /usr/sbin/dnsmasq -k