即使 avahi-resolve-host-name 成功，也无法使用 getent 解析 .local 域
Unable to resolve .local domains with getent even though avahi-resolve-host-name succeeds
正在尝试使用 CUPS 设置网络打印机。
遵循在线文档说明：
To discover or share printers using DNS-SD/mDNS, setup .local hostname
resolution with Avahi and restart cups.service.
按照说明将 Avahi 设置到 avahi-browse --all --ignore-local --resolve --terminate 和 avahi-resolve-host-name my-domain.local 都能正常工作的地步。
但是getent hosts my-domain.local无法解析。这导致 CUPS 无法打印，因为它找不到 my-printer.local.
我阅读了 mdns Github 页面，看到一条注释让我觉得我不需要 /etc/mdns.allow 文件。
nss-mdns has a simple configuration file /etc/mdns.allow for enabling
name lookups via mDNS in other domains than .local.
Note: The "minimal" version of nss-mdns does not read /etc/mdns.allow under any circumstances. It behaves as if the file
does not exist.
In the recommended configuration, no /etc/mdns.allow file is present.
但后来我看到了那个部分的最后一个注释：
If, during a request, the system-configured unicast DNS (specified in
/etc/resolv.conf) reports an SOA record for the top-level local name,
the request is rejected. Example: host -t SOA local returns something
other than Host local not found: 3(NXDOMAIN). This is the unicast SOA
heuristic.
我在我的机器上测试了它，果然，我得到了 Host local not found... 以外的东西。
添加一个包含 .local. 和 .local 行的 /etc/mdns.allow 文件，现在我可以 ping my-printer.local.
正在尝试使用 CUPS 设置网络打印机。
遵循在线文档说明：
To discover or share printers using DNS-SD/mDNS, setup .local hostname resolution with Avahi and restart cups.service.
按照说明将 Avahi 设置到 avahi-browse --all --ignore-local --resolve --terminate 和 avahi-resolve-host-name my-domain.local 都能正常工作的地步。
但是getent hosts my-domain.local无法解析。这导致 CUPS 无法打印，因为它找不到 my-printer.local.
我阅读了 mdns Github 页面，看到一条注释让我觉得我不需要 /etc/mdns.allow 文件。
nss-mdns has a simple configuration file /etc/mdns.allow for enabling name lookups via mDNS in other domains than .local.
Note: The "minimal" version of nss-mdns does not read /etc/mdns.allow under any circumstances. It behaves as if the file does not exist.
In the recommended configuration, no /etc/mdns.allow file is present.
但后来我看到了那个部分的最后一个注释：
If, during a request, the system-configured unicast DNS (specified in /etc/resolv.conf) reports an SOA record for the top-level local name, the request is rejected. Example: host -t SOA local returns something other than Host local not found: 3(NXDOMAIN). This is the unicast SOA heuristic.
我在我的机器上测试了它，果然，我得到了 Host local not found... 以外的东西。
添加一个包含 .local. 和 .local 行的 /etc/mdns.allow 文件，现在我可以 ping my-printer.local.