樹梅派DNS快取伺服器建設

Hradware: 樹梅派3B+

OS: Debian Gnu/Linux 9.4

安裝軟體：

apt-get dnsmasq

引數配置：

配置網路（無線接入）：

vi /etc/wpa_supplicant/wpa_supplicant.conf

加入無線節點SSID及連結密碼資訊，格式如下：

network={

ssid="demotest"

psk="demotest"

}

vi /etc/dhcpcd.conf

修改如下行為需要的內容：

interface wlan0

static ip_address=192.168.0.7/24

static routers=192.168.0.1

vi /etc/dhcp/dhclient.conf

將“#prepend domain-name-servers 127.0.0.1;”行內容前的“#”號刪除。

vi /etc/resolv.dnsmasq.conf

增加如下行（使用者可根據自己的DNS新增）：

nameserver 223.5.5.5

nameserver 223.6.6.6

nameserver 114.114.114.114

vi /etc/dnsmasq.conf

確保如下行存在：

domain-needed

resolv-file=/etc/resolv.dnsmasq.conf

all-servers

問題處理：

重啟後dnsmasq服務報如下錯誤：

2月 28 16:34:10 localhost dnsmasq[346]: no servers found in /run/dnsmasq/resolv.conf, will retry

2月 28 16:34:11 localhost dnsmasq[347]: Too few arguments.

需要修改/etc/default/dnsmasq檔案並將“#IGNORE_RESOLVCONF=yes”前的“#”刪除即可。

網上原貼（原文引自：https://memo.ink/dnsmasq-resolv-conf/）如下：

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systemd[1]: Starting dnsmasq - A lightweight DHCP and caching DNS server...
dnsmasq[6120]: dnsmasq: syntax check OK.
dnsmasq[6133]: started, version 2.76 cachesize 150
dnsmasq[6133]: compile time options: IPv6 GNU-getopt DBus i18n IDN DHCP DHCPv6 no-Lua TFTP conntrack ipset auth DNSSEC loop-detect inotify
dnsmasq[6133]: no servers found in /run/dnsmasq/resolv.conf, will retry
dnsmasq[6133]: read /etc/hosts - 5 addresses
systemd[1]: Started dnsmasq - A lightweight DHCP and caching DNS server.

安裝 dnsmasq 之後發現無法解析域名了，nslookup 顯示請求被拒絕。dnsmasq 的日誌顯示如上，提示讀取 /run/dnsmasq/resolv.conf 中的域名伺服器，但檔案為空，搜尋發現有直接修改該檔案的方案，但在測試後發現該檔案每次重啟 dnsmasq 服務的時候都會重新生成，修改無法儲存。

dnsmasq 在預設安裝的情況下被設定為若 resolvconf 已安裝的話，則與 resolvconf 整合。這就意味著 dnsmasq 將其監聽的地址（127.0.0.1）傳送給 resolvconf，並使用 resolvconf 的可用域名伺服器列表生成自己的上游域名伺服器列表。dnsmasq 的 resolvconf 鉤子指令碼 /etc/resolvconf/update.d/dnsmasq 生成 /var/run/dnsmasq/resolv.conf。這個指令碼在每次 resolvconf 執行的時候觸發。

需要編輯 etc/default/dnsmasq 檔案，並設定 IGNOR_RESOLVCONF=yes，這樣的話 dnsmasq 就不會直接查詢 /var/run/dnsmasq/resolv.conf 中的內容了。

/etc/init.d/dnsmasq:

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# RESOLV_CONF:
# If the resolvconf package is installed then use the resolv conf file
# that it provides as the default.  Otherwise use /etc/resolv.conf as
# the default.
#
# If IGNORE_RESOLVCONF is set in /etc/default/dnsmasq or an explicit
# filename is set there then this inhibits the use of the resolvconf-provided
# information.
#
# Note that if the resolvconf package is installed it is not possible to 
# override it just by configuration in /etc/dnsmasq.conf, it is necessary
# to set IGNORE_RESOLVCONF=yes in /etc/default/dnsmasq.
if [ ! "$RESOLV_CONF" ] &&
   [ "$IGNORE_RESOLVCONF" != "yes" ] &&
   [ -x /sbin/resolvconf ]
then
        RESOLV_CONF=/run/dnsmasq/resolv.conf
fi

自覺原創，所以大賞，多少我