Dnscrypt-proxy
dnscrypt-proxy 可以加密和認證用戶和 DNS 解析服務器之間的數據傳輸,支持 DNS over HTTPS 和 DNSCrypt,可以避免中間人攻擊和竊聽。dnscrypt-proxy 兼容 DNSSEC。
安裝[編輯 | 編輯原始碼]
安裝軟件包 dnscrypt-proxy包。
配置[編輯 | 編輯原始碼]
啟動[編輯 | 編輯原始碼]
服務有兩種啟動方式,但是只能二選一:
- 啟用
.service
listen_addresses
(即在配置文件中寫好 listen_addresses = ['127.0.0.1:53', '[::1]:53']
)- 啟用
.socket
listen_addresses
(即 listen_addresses = [ ]
),systemd 會自己配置好 socket選擇解析服務器[編輯 | 編輯原始碼]
By leaving server_names
commented out in the configuration file /etc/dnscrypt-proxy/dnscrypt-proxy.toml
, dnscrypt-proxy will choose the fastest server from the sources already configured under [sources]
[1]. The lists will be downloaded, verified, and automatically updated. [2]. Thus, configuring a specific set of servers is optional.
To manually set which server is used, edit /etc/dnscrypt-proxy/dnscrypt-proxy.toml
and uncomment the server_names
variable, selecting one or more of the servers. For example, to use Cloudflare's servers:
server_names = ['cloudflare', 'cloudflare-ipv6']
A full list of resolvers is located at the upstream page or Github. If dnscrypt-proxy has run successfully on the system before, /var/cache/dnscrypt-proxy/public-resolvers.md
will also contain a list. Look at the description for servers note which validate DNSSEC, do not log, and are uncensored. These requirements can be configured globally with the require_dnssec
, require_nolog
, require_nofilter
options.
禁用其他占用53端口的服務[編輯 | 編輯原始碼]
查看占用 53 端口的服務:
$ ss -lp 'sport = :domain'
如果輸出除了表頭還有其他內容,你就需要禁用占用53端口的那些服務,比如 systemd-resolved.service
和其他網絡管理器包含的類似服務。把它們全部幹掉,直到上面的命令的輸出只剩這個樣子:
Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port
修改 resolv.conf[編輯 | 編輯原始碼]
修改 resolv.conf,把現有的nameserver
全部清掉,添一行指向 localhost 的地址(一般是 127.0.0.1)的nameserver
;並增添一行 options [3]。示例如下:
nameserver ::1 nameserver 127.0.0.1 options edns0 single-request-reopen
其他程序可能會修改 resolv.conf,詳見:resolv.conf#Overwriting of /etc/resolv.conf。
啟動 systemd 服務[編輯 | 編輯原始碼]
根據上面你選擇的配置來 start/enable dnscrypt-proxy.service
或者 dnscrypt-proxy.socket
技巧[編輯 | 編輯原始碼]
本地 DNS 緩存配置[編輯 | 編輯原始碼]
cache = true
in your dnscrypt configuration fileIt is recommended to run DNSCrypt as a forwarder for a local DNS cache if not using dnscrypt's cache feature; otherwise, every single query will make a round-trip to the upstream resolver. Any local DNS caching program should work. In addition to setting up dnscrypt-proxy, you must setup your local DNS cache program.
修改端口[編輯 | 編輯原始碼]
In order to forward queries from a local DNS cache, dnscrypt-proxy should listen on a port different from the default 53
, since the DNS cache itself needs to listen on 53
and query dnscrypt-proxy on a different port. Port number 53000
is used as an example in this section. In this example, the port number is larger than 1024 so dnscrypt-proxy is not required to be run by root.
There are two methods for changing the default port:
Socket method
Edit dnscrypt-proxy.socket
with the following contents:
[Socket] ListenStream= ListenDatagram= ListenStream=127.0.0.1:53000 ListenDatagram=127.0.0.1:53000
When queries are forwarded from the local DNS cache to 53000
, dnscrypt-proxy.socket
will start dnscrypt-proxy.service
.
Service method
Edit the listen_addresses
option in /etc/dnscrypt-proxy/dnscrypt-proxy.toml
with the following:
listen_addresses = ['127.0.0.1:53000', '[::1]:53000']
本地 DNS 緩存配置舉例[編輯 | 編輯原始碼]
The following configurations should work with dnscrypt-proxy and assume that it is listening on port 53000
.
Unbound[編輯 | 編輯原始碼]
Configure Unbound to your liking (in particular, see Unbound#Local DNS server) and add the following lines to the end of the server
section in /etc/unbound/unbound.conf
:
do-not-query-localhost: no forward-zone: name: "." forward-addr: 127.0.0.1@53000
interface: 0.0.0.0@53
and access-control: your-network/subnet-mask allow
inside the server:
section so that the other computers can connect to the server. A client must be configured with nameserver address-of-your-server
in /etc/resolv.conf
.Restart unbound.service
to apply the changes.
dnsmasq[編輯 | 編輯原始碼]
Configure dnsmasq as a local DNS cache. The basic configuration to work with DNSCrypt:
/etc/dnsmasq.conf
no-resolv server=127.0.0.1#53000 listen-address=127.0.0.1
If you configured DNSCrypt to use a resolver with enabled DNSSEC validation, make sure to enable it also in dnsmasq:
/etc/dnsmasq.conf
proxy-dnssec
Restart dnsmasq.service
to apply the changes.
pdnsd[編輯 | 編輯原始碼]
Install pdnsd. A basic configuration to work with DNSCrypt is:
/etc/pdnsd.conf
global { perm_cache = 1024; cache_dir = "/var/cache/pdnsd"; run_as = "pdnsd"; server_ip = 127.0.0.1; status_ctl = on; query_method = udp_tcp; min_ttl = 15m; # Retain cached entries at least 15 minutes. max_ttl = 1w; # One week. timeout = 10; # Global timeout option (10 seconds). neg_domain_pol = on; udpbufsize = 1024; # Upper limit on the size of UDP messages. } server { label = "dnscrypt-proxy"; ip = 127.0.0.1; port = 53000; timeout = 4; proxy_only = on; } source { owner = localhost; file = "/etc/hosts"; }
Restart pdnsd.service
to apply the changes.
沙盒隔離[編輯 | 編輯原始碼]
Edit dnscrypt-proxy.service
to include the following lines:
[Service] CapabilityBoundingSet=CAP_IPC_LOCK CAP_SETGID CAP_SETUID CAP_NET_BIND_SERVICE ProtectSystem=strict ProtectHome=true ProtectKernelTunables=true ProtectKernelModules=true ProtectControlGroups=true PrivateTmp=true PrivateDevices=true MemoryDenyWriteExecute=true NoNewPrivileges=true RestrictRealtime=true RestrictAddressFamilies=AF_INET AF_INET6 SystemCallArchitectures=native SystemCallFilter=~@clock @cpu-emulation @debug @keyring @ipc @module @mount @obsolete @raw-io
See systemd.exec(5) and Systemd#Sandboxing application environments for more information. Additionally see upstream comments.
啟用 EDNS0[編輯 | 編輯原始碼]
Extension Mechanisms for DNS that, among other things, allows a client to specify how large a reply over UDP can be.
Add the following line to your /etc/resolv.conf
:
options edns0
You may also wish to append the following to /etc/dnscrypt-proxy.conf
:
EDNSPayloadSize <bytes>
Where <bytes> is a number, the default size being 1252, with values up to 4096 bytes being purportedly safe. A value below or equal to 512 bytes will disable this mechanism, unless a client sends a packet with an OPT section providing a payload size.
測試 EDNS0[編輯 | 編輯原始碼]
Make use of the DNS Reply Size Test Server, use the drill command line tool to issue a TXT query for the name rs.dns-oarc.net:
$ drill rs.dns-oarc.net TXT
With EDNS0 supported, the "answer section" of the output should look similar to this:
rst.x3827.rs.dns-oarc.net. rst.x4049.x3827.rs.dns-oarc.net. rst.x4055.x4049.x3827.rs.dns-oarc.net. "2a00:d880:3:1::a6c1:2e89 DNS reply size limit is at least 4055 bytes" "2a00:d880:3:1::a6c1:2e89 sent EDNS buffer size 4096"