Temporary failure resolving ftp.debian.org?

Question

linux

VDS on Debian 8, trying to install a new
apt install package

Err ftp.debian.org/debian/jessie/main...
Temporary failure resolving 'ftp.debian.org'

In /etc/resolv.conf it was 8.8.8.8, I also put Google's DNS nameserver
208.67.220.220 nameserver
8.8.8.8
nameserver 208.67.222.222
nameserver 8.8.4.4
The same (or does it take time to update?)
On the host ya.ru command
Writes: connection timed out; no servers could be reached
Hosting support says to look towards the firewall. How to understand what kind of firewall is there and what exactly needs to be tweaked in it?

Answer 1

on your own, you can define it like this:
iptables-save - will show the current settings iptables
route - will show a list of routes, is defaul set correctly?
ping 8.8.8.8 passes?
host -t A ya.ru 8.8.8.8 , should return the ip address of the host, if an error means a problem with the Internet connection,
as an option, if nothing was configured, try rebooting the host.

Answer 2

There was the same problem. Everything was decided by the team:

sudo /etc/init.d/networking restart && sudo dhclient