Faça o systemd-timesyncd não ouvir o IPv6

Question

Em um dos meus servidores (Debian 9) desabilitei o IPv6. Agora recebo o seguinte erro no syslog do sistema:

systemd-timesyncd[645]: Failed to setup connection socket: \
    Address family not supported by protocol

Como posso desabilitar o IPv6 para systemd-timesyncd?

    

Answer 1

Parece ser um bug conhecido de systemd no Arch. Não encontrou nenhuma referência para o próprio Debian, mas é possível que exista um bug similar. Do wiki do arch, postagem

relevante

systemd-timesyncd will contact servers in turn until one is found that responds. Arch uses the zones in the order of 0, 1, 2, 3. However, all pool.ntp.org zones only have IPv6 and IPv4 enabled on the 2 subdomain. All others are IPv4 only. Therefore, 2 should be placed first in order to properly provide support for IPv6/IPv4 hosts.

Também é possível que o DHCP esteja fornecendo um servidor NTP errado.

The following settings are configured in the "[Time]" section:

NTP=

A space-separated list of NTP server host names or IP addresses. During runtime this list is combined with any per-interface NTP servers acquired from systemd-networkd.service(8). systemd-timesyncd will contact all configured system or per-interface servers in turn until one is found that responds. This setting defaults to an empty list.

FallbackNTP=

A space-separated list of NTP server host names or IP addresses to be used as the fallback NTP servers. Any per-interface NTP servers obtained from systemd-networkd.service(8) take precedence over this setting, as do any servers set via NTP= above. This setting is hence only used if no other NTP server information is known. If this option is not given, a compiled-in list of NTP servers is used instead.

Solução possível: desabilitando systemd-timesyncd e instalando chrony