Debian server. How to disable\configure ipv6?

Question

Debian

Good day, good gentlemen, the hetzner.de

server has ipv6 support in addition to ipv4 . The server accesses the service in which the IP of the form 123.45.67.89 is clogged. However, the service determines not the 4th version of the IP, but 6, and therefore gives an error that the IP is incorrect. Such a change happened quite recently, from which it is not clear, I did not configure the IP itself. Apparently the server itself has now decided how ipv6 to access third-party resources. Help me configure the server so that 1. either the server accesses external services via IPv4 , 2. or disable it altogether



IPv6 and where it will lead,
3. or another less painful option .

Answer 1

Something is not entirely clear what is happening there, but, as I understand it, you just need to increase the priority of IPv4 over IPv6 when resolving a name? If so, edit the file /etc/gai.conf.
If there are already commented lines, uncomment the precedence ::ffff:0:0/96 100. If not, add it.
You can disable receiving an IPv6 address on an interface using sysctl:
net.ipv6.conf.<interfacename>.disable_ipv6 = 1

Answer 2

How to disable ipv6: const-cast.blogspot.ru/2009/11/disable-ipv6-using-...