Issue IPv6 become unusable after a while

[qtwrk]

Hi ,recently I install plesk 17.5.3 on centos 7.4 with ipv6 properly configured (tested by ping6 google.com and it works)

and then I congifured my sited to run on ipv6 , for the first , it works , but after a while , ipv6 is not longer working.

ping6 google.com returns Destination unreachable: Address unreachable.

this problem seems to be spontaneous, and reboot appears to fix issue.

but I can't just reboot server every now and then ...

any help would much appreciated.

 

[Bitpalast]

When the issue occurs, is your IPv6 network address still reachable in general? This is probably not a network IPv6 issue. It can equally well be an issue with another service that becomes unresponsive. For example you might find more details in the plesk-php<version>-fpm log files or the /httpd/error_log log file or the log file of a specific virtual host you are trying to reach. Did you check whether the web server service is up (# service nginx status, # service httpd status)? Are you using the DNS service on the machine? Is it running? Are you using a firewall?

 

[qtwrk]

When the issue occurs, is your IPv6 network address still reachable in general? This is probably not a network IPv6 issue. It can equally well be an issue with another service that becomes unresponsive. For example you might find more details in the plesk-php<version>-fpm log files or the /httpd/error_log log file or the log file of a specific virtual host you are trying to reach. Did you check whether the web server service is up (# service nginx status, # service httpd status)? Are you using the DNS service on the machine? Is it running? Are you using a firewall?

I think I found the source of problem , but I am unable to solve it.

by traceroute6 , I found this problem , host unreachable.