在分配租约之前在 dnsmasq 中初始化 DNS

Question

我在 debian wheezy 和 jessie 上测试了这一点，原帖作者确认它在 stretch 上也能正常工作。Stretch 和 jessie 确实使用 resolvconf，而 wheezy 则不使用。

只需将所有固定 IP 地址放入/etc/hosts运行 dnsmasq 的主机本地的文件中即可。您可在此处添加本地网络上具有固定地址的主机（本例中为域local.net、IP 192.168.0.xxx）或因某种原因想要在本地覆盖的主机：

# /etc/hosts
# the local host
127.0.0.1       localhost

# provide fixed addresses used by dnsmasq for the local network
192.168.0.100   host0.local.net             host0
192.168.0.101   host1.local.net             host1
192.168.0.102   host2.local.net             host2

# map a fancy service to the same address as above (e.g. on host2)
192.168.0.102   imap.local.net              imap
192.168.0.102   mediaserver.local.net       mediaserver

# overwrite an external host with address 1.2.3.4
1.2.3.4    some.external-host.com
# map unwanted external hosts to localhost
127.0.0.1  some.malicious-advertising-server.com

Dnsmasq 优先读取主机文件而不是调用外部解析器。因此，该文件中的所有 IP 都应该在这些主机请求租约（甚至运行）之前可用。确保在您的中注释掉以下内容/etc/dnsmasq.conf：

# /etc/dnsmasq.conf
...
# If you don't want dnsmasq to read /etc/hosts, uncomment the
# following line.
#no-hosts
...

如果您的域名local.net不是公开可用的域名，请将其放入以下子句中，以防止 dnsmaq 查询不存在域名的上游解析器：

# /etc/dnsmasq.conf
...
# Add local-only domains here, queries in these domains are answered
# from /etc/hosts or DHCP only.
local=/local.net/
...

您可能想要查看/etc/hosts有关中的文件的更多选项/etc/dnsmasq.conf。周围的评论非常有用。

现在您要将物理主机映射到这些 IP 地址。如果不存在，请创建文件/etc/ethers。在此文件中，您将放置应获得固定 IP 地址的所有主机的 MAC 地址，后跟其相应的 dns 名称：

# /etc/ethers
1C:6F:65:39:09:8D host0.local.net
1C:6F:65:39:19:8D host1.local.net
1C:6F:65:39:29:8D host2.local.net

您只需要您的物理主机，而不是您在上面的文件中定义的其他服务名称/etc/hosts。返回并检查是否已启用/etc/dnsmasq.conf读取：/etc/ethers

# /etc/dnsmasq.conf
...
# If this line is uncommented, dnsmasq will read /etc/ethers and act
# on the ethernet-address/IP pairs found there just as if they had
# been given as --dhcp-host options. Useful if you keep
# MAC-address/host mappings there for other purposes.
read-ethers

同样，还有更多选项/etc/ethers。如果您需要更多功能，您可能需要浏览它们。

第三步，您必须说服 resolveconf 使用本地 dnsmasq 作为第一个解析器。否则，在运行 dnsmasq 的主机上，动态租约（而不是上面配置的固定租约）的解析将无法正常工作。我的如下所示/etc/resolvconf.conf：

# /etc/resolvconf.conf
# Configuration for resolvconf(8)
# See resolvconf.conf(5) for details

resolv_conf=/etc/resolv.conf
# If you run a local name server, you should uncomment the below line and
# configure your subscribers configuration files below.
name_servers=127.0.0.1

# Mirror the Debian package defaults for the below resolvers
# so that resolvconf integrates seemlessly.
dnsmasq_resolv=/var/run/dnsmasq/resolv.conf
pdnsd_conf=/etc/pdnsd.conf
unbound_conf=/var/cache/unbound/resolvconf_resolvers.conf

这里的关键是：

# /etc/resolvconf.conf
...
name_servers=127.0.0.1
...

它告诉解析器使用本地主机作为第一个解析器。这里的问题是 dnsmasq 也使用 resolvconf 来解析未知地址。但不用担心，dnsmasq 足够聪明，可以避免在递归循环中调用自身。

最后（可能很明显）一件事：如果您也定义了动态 IP 范围，例如为客人，移动设备等，请确保它不会与给出的地址冲突/etc/hosts：

# /etc/dnsmasq.conf
...
# Uncomment this to enable the integrated DHCP server, you need
# to supply the range of addresses available for lease and optionally
# a lease time. If you have more than one network, you will need to
# repeat this for each network on which you want to supply DHCP
# service.
dhcp-range=192.168.0.50,192.168.0.99,12h
# this range must not include above addresses given in /etc/hosts
...

现在 dnsmaq 从文件中获取 IP 地址/etc/hosts，而不管现有租约如何。DHCP 请求使用将 MAC 地址解析/etc/ethers为域名，然后使用将 MAC 地址解析为 IP /etc/hosts。

因此，您可以在单独的文件中整齐地配置主机和以太，而不需要将每个主机放入...'选项/etc/dnsmaq.conf中。dhcp-host

Answer 1