本页面未完整翻译。请帮助完成翻译。
(一旦移除本段，表示翻译已经完成)
DHCP 和 DNS 示例
This article relies on the following:
Accessing web interface / command-line interface
Managing configs / packages / services / logs
See also:
DHCP and DNS configuration,
DNS 加密,
DNS 劫持
介绍
本指南提供了适用于 OpenWrt 的最常见的 dnsmasq 和 odhcpd 调整方案。
说明
静态租约
LuCI → DHCP/DNS → 静态地址分配
为具有 MAC 地址的计算机添加固定 IPv4 地址 192.168.1.22 和名称 mylaptop。
uci add dhcp host
uci set dhcp.@host[-1].name="mylaptop"
uci set dhcp.@host[-1].dns='1'
uci set dhcp.@host[-1].mac="11:22:33:44:55:66"
uci set dhcp.@host[-1].ip="192.168.1.22"
uci commit dhcp
service dnsmasq restart
Reconnect your clients to apply the changes.
Add a fixed IPv6 interface identifier aka address suffix 23 and name mylaptop for a machine with the DUID 000100004fd454041c6f65d26f43.
uci add dhcp host
uci set dhcp.@host[-1].name="mylaptop"
uci set dhcp.@host[-1].dns='1'
uci set dhcp.@host[-1].duid="000100004fd454041c6f65d26f43"
uci set dhcp.@host[-1].hostid="23"
uci commit dhcp
service odhcpd restart
Reconnect your clients to apply the changes.
This is an implementation of the --dhcp-host option.
You can combine IPv4 and IPv6 reservations to a single host entry.
Using multiple MACs per host entry is possible but unreliable.
Add a separate host entry for each MAC if the host has more than one interface connected simultaneously.
See also: odhcpd leases
MAC filtering
Ignore DHCP requests from specific clients.
uci add dhcp host
uci set dhcp.@host[-1].name="mydesktop"
uci set dhcp.@host[-1].mac="00:11:22:33:44:55"
uci set dhcp.@host[-1].ip="ignore"
uci commit dhcp
service dnsmasq restart
Ignore all DHCP requests except the ones from known clients configured with static leases or /etc/ethers.
uci set dhcp.lan.dynamicdhcp="0"
uci commit dhcp
service dnsmasq restart
Avoid using this as a security measure since the client can still access the network with a static IP.
Race conditions with netifd
Resolve the race condition with netifd service and skip check for competing DHCP servers.
uci set dhcp.lan.force="1"
uci commit dhcp
service dnsmasq restart
Missing public prefix
Suppress warnings about missing GUA prefix.
uci set dhcp.odhcpd.loglevel="3"
uci commit dhcp
service odhcpd restart
Providing IPv6 default route with DHCP
Announce IPv6 default route for clients using the ULA prefix.
uci set dhcp.lan.ra_default="1"
uci commit dhcp
service odhcpd restart
DHCP options
DHCP options can be configured under the DHCP pool section via dhcp_option.
Use an alternative default gateway, DNS server and NTP server, disable WINS.
uci add_list dhcp.lan.dhcp_option="3,192.168.1.2"
uci add_list dhcp.lan.dhcp_option="6,172.16.60.64"
uci add_list dhcp.lan.dhcp_option="42,172.16.60.64"
uci add_list dhcp.lan.dhcp_option="44"
uci commit dhcp
service dnsmasq restart
Client classifying and individual options
Use the tag classifier to create a tagged group.
Assign individual DHCP options to hosts tagged with tag1.
Specify custom DNS and possibly other DHCP options.
uci set dhcp.tag1="tag"
uci set dhcp.tag1.dhcp_option="6,8.8.8.8,8.8.4.4"
uci add dhcp host
uci set dhcp.@host[-1].name="j400"
uci set dhcp.@host[-1].mac="00:21:63:75:aa:17"
uci set dhcp.@host[-1].ip="10.11.12.14"
uci set dhcp.@host[-1].tag="tag1"
uci add dhcp host
uci set dhcp.@host[-1].name="j500"
uci set dhcp.@host[-1].mac="01:22:64:76:bb:18"
uci set dhcp.@host[-1].ip="10.11.12.15"
uci set dhcp.@host[-1].tag="tag1"
uci commit dhcp
service dnsmasq restart
Use the mac classifier to create a tagged group.
Assign different DHCP options to hosts with matching MACs.
Disable default gateway and specify custom DNS.
uci set dhcp.mac1="mac"
uci set dhcp.mac1.mac="00:FF:*:*:*:*"
uci set dhcp.mac1.networkid="vpn"
uci add_list dhcp.mac1.dhcp_option="3"
uci add_list dhcp.mac1.dhcp_option="6,192.168.1.3"
uci commit dhcp
service dnsmasq restart
Use vendor-specific DHCP option to disable NetBios over TCP for Windows Clients
See also: Vendor-Specific Option Code 0x01 - Microsoft Disable NetBIOS Option
If you want to disable NetBIOS over TCP on Windows clients, it's possible with the following vendor-specific DHCP option:
DHCP Option 43 (Vendor Specific Information)
Vendor-specific Option Code (1 byte): 0x01 (Microsoft Disable NetBios Option)
Vendor-specific Option Length (1 byte): 0x04
Vendor-specific Option Data (4 bytes): See table below
Value Effect
0x00000000 Enable NetBIOS over TCP/IP
0x00000001 Ignore setting
0x00000002 Disable NetBIOS over TCP/IP
It needs to be pushed to clients who have the “MSFT 5.0” Vendor class identifier in their DHCP requests.
This can be achieved with the following configuration snippet:
uci set dhcp.msft="vendorclass"
uci set dhcp.msft.networkid="msft"
uci set dhcp.msft.vendorclass="MSFT"
uci add_list dhcp.msft.dhcp_option="vendor:MSFT,1,2i"
uci commit dhcp
service dnsmasq restart
DHCP pool for a large network
10.0.0.0 - network address
255.0.0.0 - network mask
10.22.0.1 - pool start
10.22.0.254 - pool end
22*2**16+1 - pool offset
253 - pool limit
# ipcalc.sh 10.0.0.0 255.0.0.0 $((22*2**16+1)) 253
IP=10.0.0.0
NETMASK=255.0.0.0
BROADCAST=10.255.255.255
NETWORK=10.0.0.0
PREFIX=8
START=10.22.0.1
END=10.22.0.254
uci set dhcp.lan.start="$((22*2**16+1))"
uci set dhcp.lan.limit="253"
uci commit dhcp
service dnsmasq restart
Hostnames
LuCI → Network → Hostnames
Define a custom domain name and the corresponding PTR record - assigns the IPv4 address 192.168.1.23 and IPv6 address fdce::23 to the domain name mylaptop and construct an appropriate reverse records.
You can also use this to rebind domain names.
The init service merges all entries to an additional hosts file used with the --addn-hosts option.
uci add dhcp domain
uci set dhcp.@domain[-1].name="mylaptop"
uci set dhcp.@domain[-1].ip="192.168.1.23"
uci add dhcp domain
uci set dhcp.@domain[-1].name="mylaptop"
uci set dhcp.@domain[-1].ip="fdce::23"
uci commit dhcp
service dnsmasq restart
Be sure to set up static leases to avoid possible collisions due to race conditions.
A and AAAA RR
This is an implementation of the --address option.
Return 10.10.10.1 for the domain home and all its subdomains.
uci add_list dhcp.@dnsmasq[0].address="/home/10.10.10.1"
uci commit dhcp
service dnsmasq restart
SRV RR
This is an implementation of the --srv-host option.
Define an SRV record for SIP over UDP, with the default port of 5060 on the host pbx.mydomain.com, with a class of 0 and a weight of 10.
uci add dhcp srvhost
uci set dhcp.@srvhost[-1].srv="_sip._udp.mydomain.com"
uci set dhcp.@srvhost[-1].target="pbx.mydomain.com"
uci set dhcp.@srvhost[-1].port="5060"
uci set dhcp.@srvhost[-1].class="0"
uci set dhcp.@srvhost[-1].weight="10"
uci commit dhcp
service dnsmasq restart
CNAME RR
This is an implementation of the --cname option.
A Canonical Name record specifies that a domain name is an alias for another domain, the “canonical” domain.
Specify that the FTP server is on the same host as the web server.
uci add dhcp cname
uci set dhcp.@cname[-1].cname="ftp.example.com"
uci set dhcp.@cname[-1].target="www.example.com"
uci commit dhcp
service dnsmasq restart
Be sure to set up hostnames since CNAME depends on it.
MX RR
This is an implementation of the --mx-host option.
Mitigate the issues caused by split DNS for your own domain if you're running the mail server for your domain behind a firewall.
Convince that mailer that it's actually authoritative for your domain, otherwise sendmail may not find an MX record to confirm that the domain is an MX relay and complain about non-existent domain of sender address.
uci add dhcp mxhost
uci set dhcp.@mxhost[-1].domain="yyy.zzz"
uci set dhcp.@mxhost[-1].relay="my.host.com"
uci set dhcp.@mxhost[-1].pref="10"
uci commit dhcp
service dnsmasq restart
TFTP boot
Direct BOOTP requests to the TFTP server.
Tell the client to load pxelinux.0 from the server at 192.168.1.2, and mount root from /data/netboot/root on the same server.
uci set dhcp.linux="boot"
uci set dhcp.linux.filename="/tftpboot/pxelinux.0"
uci set dhcp.linux.serveraddress="192.168.1.2"
uci set dhcp.linux.servername="fileserver"
uci add_list dhcp.linux.dhcp_option="option:root-path,192.168.1.2:/data/netboot/root"
uci commit dhcp
service dnsmasq restart
Multi-Arch TFTP boot
For PXE boot, each client needs a specific binary for its architecture e.g. PC BIOS, UEFI x86 32bit, UEFI x86 64bit, ARM, etc.
You can match on the DHCP “Vendor Class Identifier” option (60) specified by the client to send back the right filename.
uci set dhcp.@dnsmasq[0].logdhcp='1'
uci set dhcp.@dnsmasq[0].enable_tftp='1'
uci set dhcp.@dnsmasq[0].tftp_root='/srv/tftp'
uci add dhcp match
uci set dhcp.@match[-1].networkid='bios'
uci set dhcp.@match[-1].match='60,PXEClient:Arch:00000'
uci add dhcp match
uci set dhcp.@match[-1].networkid='efi32'
uci set dhcp.@match[-1].match='60,PXEClient:Arch:00006'
uci add dhcp match
uci set dhcp.@match[-1].networkid='efi64'
uci set dhcp.@match[-1].match='60,PXEClient:Arch:00007'
uci add dhcp match
uci set dhcp.@match[-1].networkid='efi64'
uci set dhcp.@match[-1].match='60,PXEClient:Arch:00009'
uci add dhcp boot
uci set dhcp.@boot[-1].filename='tag:bios,bios/lpxelinux.0'
uci set dhcp.@boot[-1].serveraddress="$(uci get network.lan.ipaddr)"
uci set dhcp.@boot[-1].servername="$(uci get system.@system[0].hostname)"
uci add dhcp boot
uci set dhcp.@boot[-1].filename='tag:efi32,efi32/syslinux.efi'
uci set dhcp.@boot[-1].serveraddress="$(uci get network.lan.ipaddr)"
uci set dhcp.@boot[-1].servername="$(uci get system.@system[0].hostname)"
uci add dhcp boot
uci set dhcp.@boot[-1].filename='tag:efi64,efi64/syslinux.efi'
uci set dhcp.@boot[-1].serveraddress="$(uci get network.lan.ipaddr)"
uci set dhcp.@boot[-1].servername="$(uci get system.@system[0].hostname)"
uci commit dhcp
service dnsmasq reload
Multiple DHCP/DNS server/forwarder instances
If you need multiple DNS forwarders with different configurations or DHCP server with different sets of lease files.
Running multiple dnsmasq instances as DNS forwarder and/or DHCPv4 server, each having their own configuration and lease list can be configured by creating multiple dnsmasq sections.
Typically in such configs each dnsmasq section will be bound to a specific interface by using the interface list; assigning sections like dhcp, host, etc. to a specific dnsmasq instance is done by the instance option.
By default dnsmasq adds the loopback interface to the interface list to listen when the --interface option is used; therefore the loopback interface needs to be excluded in one of the dnsmasq instances by using the notinterface list.
These are example settings for multiple dnsmasq instances each having their own dhcp section.
dnsmasq instance lan_dns is bound to the lan interface while the dnsmasq instance guest_dns is bound to the guest interface.
# Remove default instances
while uci -q delete dhcp.@dnsmasq[0]; do :; done
while uci -q delete dhcp.@dhcp[0]; do :; done
# Use network interface names for DHCP/DNS instance names
INST="lan guest"
for INST in ${INST}
do
uci set dhcp.${INST}_dns="dnsmasq"
uci set dhcp.${INST}_dns.domainneeded="1"
uci set dhcp.${INST}_dns.boguspriv="1"
uci set dhcp.${INST}_dns.filterwin2k="0"
uci set dhcp.${INST}_dns.localise_queries="1"
uci set dhcp.${INST}_dns.rebind_protection="1"
uci set dhcp.${INST}_dns.rebind_localhost="1"
uci set dhcp.${INST}_dns.local="/${INST}/"
uci set dhcp.${INST}_dns.domain="${INST}"
uci set dhcp.${INST}_dns.expandhosts="1"
uci set dhcp.${INST}_dns.nonegcache="0"
uci set dhcp.${INST}_dns.authoritative="1"
uci set dhcp.${INST}_dns.readethers="1"
uci set dhcp.${INST}_dns.leasefile="/tmp/dhcp.leases.${INST}"
uci set dhcp.${INST}_dns.resolvfile="/tmp/resolv.conf.d/resolv.conf.auto"
uci set dhcp.${INST}_dns.nonwildcard="1"
uci add_list dhcp.${INST}_dns.interface="${INST}"
uci add_list dhcp.${INST}_dns.notinterface="loopback"
uci set dhcp.${INST}="dhcp"
uci set dhcp.${INST}.instance="${INST}_dns"
uci set dhcp.${INST}.interface="${INST}"
uci set dhcp.${INST}.start="100"
uci set dhcp.${INST}.limit="150"
uci set dhcp.${INST}.leasetime="12h"
done
uci -q delete dhcp.@dnsmasq[0].notinterface
uci commit dhcp
service dnsmasq restart
The LuCI web interface has not been updated to support multiple dnsmasq instances.
Logging DNS queries
LuCI → 网络 → DHCP/DNS → 常规设置 → 记录查询日志
Log DNS queries for troubleshooting.
uci set dhcp.@dnsmasq[0].logqueries="1"
uci commit dhcp
service dnsmasq restart
See also: Reading logs
Disabling DHCP role
This change turns off DHCP on the specified interface but leaves DNS services available.
uci set dhcp.lan.ignore="1"
uci commit dhcp
service dnsmasq restart
service odhcpd restart
为 odhcpd 禁用 IPv6 DNS
Stop advertising IPv6 DNS with DHCPv6/RA.
uci set dhcp.lan.dns_service="0"
uci set dhcp.lan.ra_dns="0"
uci commit dhcp
service odhcpd restart
Disabling DNS role
This is useful when you just want to hand out addresses to clients, without doing any DNS by dnsmasq.
service dnsmasq stop
uci set dhcp.@dnsmasq[0].localuse="0"
uci set dhcp.@dnsmasq[0].port="0"
uci commit dhcp
service dnsmasq start
Replacing dnsmasq with odhcpd and Unbound
Remove dnsmasq and use odhcpd for both DHCP and DHCPv6.
opkg update
opkg remove dnsmasq odhcpd-ipv6only
opkg install odhcpd
uci -q delete dhcp.@dnsmasq[0]
uci set dhcp.lan.dhcpv4="server"
uci set dhcp.odhcpd.maindhcp="1"
uci commit dhcp
service odhcpd restart
对 DNS 使用 Unbound.
opkg update
opkg install unbound-control unbound-daemon
uci set unbound.@unbound[0].add_local_fqdn="3"
uci set unbound.@unbound[0].add_wan_fqdn="1"
uci set unbound.@unbound[0].dhcp_link="odhcpd"
uci set unbound.@unbound[0].dhcp4_slaac6="1"
uci set unbound.@unbound[0].unbound_control="1"
uci commit unbound
service unbound restart
uci set dhcp.odhcpd.leasetrigger="/usr/lib/unbound/odhcpd.sh"
uci commit dhcp
service odhcpd restart
See also: Unbound official documentation
使用 DHCP 提供自定义 DNS
LuCI → 网络 → 接口 → LAN → 编辑 → DHCP 服务器
高级设置 → DHCP 选项
IPv6 设置 → 通告的 IPv6 DNS 服务器
使用 DHCP 通告自定义 DNS 服务器。
# Configure dnsmasq
uci -q delete dhcp.lan.dhcp_option
uci add_list dhcp.lan.dhcp_option="6,8.8.8.8,8.8.4.4"
uci commit dhcp
service dnsmasq restart
# Configure odhcpd
uci -q delete dhcp.lan.dns
uci add_list dhcp.lan.dns="2001:4860:4860::8888"
uci add_list dhcp.lan.dns="2001:4860:4860::8844"
uci commit dhcp
service odhcpd restart
重新连接您的客户端以应用更改。
See also:
ISP DNS with DHCP,
IPv6 ISP DNS with DHCPv6
Providing DNS for non-local networks
Answer DNS queries arriving from non-local networks.
Reply to VPN clients using point-to-point topology.
uci set dhcp.@dnsmasq[0].localservice="0"
uci commit dhcp
service dnsmasq restart
禁用 DNS 缓存
禁用 DNS 缓存。
uci set dhcp.@dnsmasq[0].cachesize="0"
uci commit dhcp
service dnsmasq restart
DNS 转发
LuCI → 网络 → DHCP/DNS → 常规设置 → DNS 转发
将DNS查询转发到特定服务器。
uci -q delete dhcp.@dnsmasq[0].server
uci add_list dhcp.@dnsmasq[0].server="8.8.8.8"
uci add_list dhcp.@dnsmasq[0].server="8.8.4.4"
uci commit dhcp
service dnsmasq restart
这可以与选择性 DNS 转发相结合。
Split DNS
LuCI → 网络 → DHCP/DNS → HOSTS 和解析文件 → 忽略解析文件
Ignore resolvfile option and limit upstream resolvers to server option.
This effectively enables split DNS and makes the local system not to use dnsmasq.
service dnsmasq stop
uci set dhcp.@dnsmasq[0].noresolv="1"
uci commit dhcp
service dnsmasq start
Enforcing dnsmasq for local system
Enforce local system to use dnsmasq if it is running with noresolv option.
Beware of race condition with Adblock service when using DNS encryption.
uci set dhcp.@dnsmasq[0].localuse="1"
uci commit dhcp
service dnsmasq restart
Selective DNS forwarding
LuCI → 网络 → DHCP/DNS → 常规设置 → DNS 转发
Forward DNS queries for a specific domain and all its subdomains to a different server.
More specific domains take precedence over less specific domains.
uci add_list dhcp.@dnsmasq[0].server="/example.com/192.168.2.1"
uci commit dhcp
service dnsmasq restart
This can be combined with unconditional DNS forwarding.
DNS 过滤
LuCI → 网络 → DHCP/DNS → 常规设置 → DNS 转发
Simple DNS-based content filtering.
# Blacklist
uci add_list dhcp.@dnsmasq[0].server="/example.com/"
uci add_list dhcp.@dnsmasq[0].server="/example.net/"
uci commit dhcp
service dnsmasq restart
# Whitelist
uci add_list dhcp.@dnsmasq[0].server="/example.com/#"
uci add_list dhcp.@dnsmasq[0].server="/example.net/#"
uci add_list dhcp.@dnsmasq[0].server="/#/"
uci commit dhcp
service dnsmasq restart
See also:
Ad blocking,
DNS-based firewall with IP sets
Race conditions with sysntpd
Resolve the race condition with sysntpd service.
When running dnsmasq with noresolv and localuse options and using DNS encryption for local system.
Fetch peer DNS or use a fallback DNS provider.
Bypass DNS forwarding for NTP provider.
. /lib/functions/network.sh
network_flush_cache
for IPV in 4 6
do eval network_find_wan${IPV%4} NET_IF
network_get_dnsserver NET_DNS "${NET_IF}"
case ${IPV} in
(4) NET_DNS="${NET_DNS:-8.8.8.8 8.8.4.4}" ;;
(6) NET_DNS="${NET_DNS:-2001:4860:4860::8888 2001:4860:4860::8844}" ;;
esac
for NET_DNS in ${NET_DNS}
do uci get system.ntp.server \
| sed -e "s/\s/\n/g" \
| sed -r -e "/\.pool\.ntp\.org$/s|^[0-9]*\.||;s|.*|\
del_list dhcp.@dnsmasq[0].server='/\0/${NET_DNS}'\n\
add_list dhcp.@dnsmasq[0].server='/\0/${NET_DNS}'|" \
| uci -q batch
done
done
uci commit dhcp
service dnsmasq restart
上游 DNS 提供商
LuCI → 网络 → 接口 → WAN & WAN6 → 编辑
Use DNS servers advertised by peer
使用自定义的 DNS 服务器
OpenWrt uses peer DNS as the upstream resolvers for dnsmasq by default.
这些通常由 ISP 上游 DHCP 服务器提供。
您可以将其更改为任何其他 DNS 提供商 或运行在其他主机上的本地 DNS 服务器。
如有必要，请使用支持 DNSSEC 验证的解析器。
指定多个解析器以提高容错能力。
# 配置 DNS 提供商
uci -q delete network.wan.dns
uci add_list network.wan.dns="8.8.8.8"
uci add_list network.wan.dns="8.8.4.4"
# 配置 IPv6 DNS 提供商
uci -q delete network.wan6.dns
uci add_list network.wan6.dns="2001:4860:4860::8888"
uci add_list network.wan6.dns="2001:4860:4860::8844"
# Disable peer DNS
uci set network.wan.peerdns="0"
uci set network.wan6.peerdns="0"
# 保存并应用
uci commit network
service network restart
一般注意事项
Resolvers from all active interfaces are combined in a single runtime configuration indiscriminately.
If the interface is down, its resolvers are not used, so it's reasonable to specify resolvers only on interfaces they are reachable from.
Dnsmasq 定期查询所有列出的解析器，然后在一段时间内使用最快的解析器。
多个 DNS 提供商
The more DNS providers, the higher the fault tolerance of your DNS relative to DoS.
Different DNS providers may return different answers to a DNS query due to differences in caching, synchronization, load balancing, content filtering, etc.
To distinguish between correct and incorrect answers such as false-negatives, you need to utilize DNSSEC which may negatively impact fault tolerance and performance.
Peer DNS options
Keep peer DNS enabled to improve your DNS fault tolerance.
Disable peer DNS to prevent DNS leaks if you have configured a VPN connection on OpenWrt.
Disable peer DNS to actually change your DNS provider and receive more predictable DNS replies.
This website uses cookies. By using the website, you agree with storing cookies on your computer. Also you acknowledge that you have read and understand our Privacy Policy. If you do not agree leave the website.OKMore information about cookies