Why doesn't the ping command work?

Question

linux

Previously, the command was executed correctly, recently, when trying to call the command, it gives the answer in the following form:

[email protected]:~# ping google.com
PING google.com(ams15s21-in-x0e.*****.net (2a*0:***:400e:***::***e)) 56 data bytes
From ubuntu (2a09:****::***) icmp_seq=1 Destination unreachable: Address unreachable
From ubuntu (2a09:****::***) icmp_seq=2 Destination unreachable: Address unreachable
From ubuntu (2a09:****::***) icmp_seq=3 Destination unreachable: Address unreachable
From ubuntu (2a09:****::***) icmp_seq=4 Destination unreachable: Address unreachable
From ubuntu (2a09:****::***) icmp_seq=5 Destination unreachable: Address unreachable
From ubuntu (2a09:****::***) icmp_seq=6 Destination unreachable: Address unreachable
From ubuntu (2a09:****::***) icmp_seq=7 Destination unreachable: Address unreachable
^C
--- google.com ping statistics ---
9 packets transmitted, 0 received, +7 errors, 100% packet loss, time 8165ms

I added several pieces of IPv6 to the hoster panel, but I didn’t use them anywhere, now they have been removed, but the ping seems to be associated with these addresses.

Local host addresses and domains that are pinged on this server are normal. Tell me how to fix ping?))

Answer 1

The server is assigned an IPv6 address, so those domain names on the Internet for which the pinged DNS query returns an AAAA record are attempted to ping the IPv6 address. But apparently something is missing for IPv6 to work correctly (routing is not configured / incorrect server IPv6 address / IPv6 configuration error on the hosting side / something else), so the ping does not reach the target host and you get a response that address is not available.
"How to fix" depends on which repair option is most suitable for you. Options:
- remove public IPv6 addresses from all network interfaces on the server, so that the system becomes IPv4-only, ping attempts to IPv6 addresses should stop;
- explicitly tell the ping utility to use the resolve only in IPv4 addresses by specifying the parameter-4when calling the ping command;
- Ask your hosting provider for help in configuring IPv6.