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linux:dnsmasq

dnsmasq DHCP + DNS сервера в одной службе

dnsmasq это DHCP и DNS сервера в одной программе. Большой плюс для домашней локальной сети это кэширование DNS запросов, что дало отличный прирост скорости работы с интернетом. Еще интересный бонус - запросы в разные зоны можно направлять на разные DNS сервера, что удобно если у провайдера свои сайты. Далее на Dnsmasq.

aptitude install dnsmasq

Копируем конфигурационный файл:

mv /etc/dnsmasq.conf /etc/dnsmasq.conf.install

Создаем конфигурационный файл:

nano /etc/dnsmasq.conf

Текст конфигурационного файла с комментариями параметров, тех что найдены и поняты.

dnsmasq.conf
############
############ настройки DNS 
############
# прослушивать на этом конкретном порту вместо стандартного порта DNS, утановка в 0 отключает функцию DNS, только DHCP или TFTP.
#port=5353
 
# никогда не пересылать простые текстовые запросы (без точки или без части домена)
domain-needed
 
# никогда не пересылать не маршрутизированные адреса
bogus-priv
 
#блокировка всеx SRV запросы. Не используйте эту настройку, если используете Kerberos, SIP, XMMP и Google-talk и т.п.
# SRV записи указанные в srv-host= не блокируются этим параметром
filterwin2k
 
#Изменить местонахождение файла /etc/resolv.conf
#resolv-file=
 
# запрашивать DNS строго в порядке следования из /etc/resolv.conf
strict-order
 
# рамер кэша, максимум 10000
cache-size=10001
 
#не кешировать битые ответы
no-negcache
 
#список вышестоящих DNS, запросы на домен vbg засылать на ... DNS
server=/local_domain/192.168.0.100
server=/to/8.8.8.8
server=8.8.8.8
 
# If you don't want dnsmasq to read /etc/resolv.conf or any other
# file, getting its servers from this file instead (see below), then
# uncomment this.
#no-resolv
 
# If you don't want dnsmasq to poll /etc/resolv.conf or other resolv
# files for changes and re-read them then uncomment this.
#no-poll
 
# Add other name servers here, with domain specs if they are for
# non-public domains.
#server=/localnet/192.168.0.1
 
# Example of routing PTR queries to nameservers: this will send all
# address->name queries for 192.168.3/24 to nameserver 10.1.2.3
#server=/3.168.192.in-addr.arpa/10.1.2.3
 
# Add local-only domains here, queries in these domains are answered
# from /etc/hosts or DHCP only.
#local=/localnet/
 
#произвольная доменная адресация, можно направить любой запрос на любой адрес
address=/mypc.home/192.168.0.1
 
 
# --address (and --server) work with IPv6 addresses too.
#address=/www.thekelleys.org.uk/fe80::20d:60ff:fe36:f83
 
# You can control how dnsmasq talks to a server: this forces
# queries to 10.1.2.3 to be routed via eth1
# server=10.1.2.3@eth1
 
# and this sets the source (ie local) address used to talk to
# 10.1.2.3 to 192.168.1.1 port 55 (there must be a interface with that
# IP on the machine, obviously).
# server=10.1.2.3@192.168.1.1#55
 
# If you want dnsmasq to change uid and gid to something other
# than the default, edit the following lines.
#user=
#group=
 
# по умолчанию dnsmasq "слушает" DNS запросы со всех
# интерфейсов в системе, если в системе несколько интерфейсов
# (enp1s0,enp2s0,...и т.д.), но только один физически подключен к
# локальной сети, например только enp1s0
interface=enp1s0
# Or you can specify which interface _not_ to listen on
#except-interface=
# Принимаем запросы на локальном адресе
listen-address=127.0.0.1,192.168.0.1
 
#не предоставлять DHCP или TFTP сервисы на указанном интерфейсе (это не отключает DNS сервис)
no-dhcp-interface=lo
no-dhcp-interface=enp2s0
 
# позволять запускать более одной копии процесса
bind-interfaces
 
# If you don't want dnsmasq to read /etc/hosts, uncomment the
# following line.
#no-hosts
# or if you want it to read another file, as well as /etc/hosts, use
# this.
#addn-hosts=/etc/banner_add_hosts
 
# Set this (and domain: see below) if you want to have a domain
# automatically added to simple names in a hosts-file.
#expand-hosts
 
# Set the domain for dnsmasq. this is optional, but if it is set, it
# does the following things.
# 1) Allows DHCP hosts to have fully qualified domain names, as long
#     as the domain part matches this setting.
# 2) Sets the "domain" DHCP option thereby potentially setting the
#    domain of all systems configured by DHCP
# 3) Provides the domain part for "expand-hosts"
#domain=thekelleys.org.uk
 
# Set a different domain for a particular subnet
#domain=wireless.thekelleys.org.uk,192.168.2.0/24
 
# Same idea, but range rather then subnet
#domain=reserved.thekelleys.org.uk,192.68.3.100,192.168.3.200
 
 
############
############ настройки DHCP 
############
 
# диапазон адресов для сети и время аренды (включает DHCP)
dhcp-range=192.168.0.10,192.168.0.25,24h
 
# максимальное количество назначений адресов
dhcp-lease-max=150
 
# куда сохранять базу выданных адресов
dhcp-leasefile=/var/lib/misc/dnsmasq.leases
 
#авторитаризм в сети
dhcp-authoritative
 
 
# This is an example of a DHCP range which sets a tag, so that
# some DHCP options may be set only for this network.
#dhcp-range=set:red,192.168.0.50,192.168.0.150
 
# Use this DHCP range only when the tag "green" is set.
#dhcp-range=tag:green,192.168.0.50,192.168.0.150,12h
 
# Specify a subnet which can't be used for dynamic address allocation,
# is available for hosts with matching --dhcp-host lines. Note that
# dhcp-host declarations will be ignored unless there is a dhcp-range
# of some type for the subnet in question.
# In this case the netmask is implied (it comes from the network
# configuration on the machine running dnsmasq) it is possible to give
# an explicit netmask instead.
#dhcp-range=192.168.0.0,static
 
# Enable DHCPv6. Note that the prefix-length does not need to be specified
# and defaults to 64 if missing/
#dhcp-range=1234::2, 1234::500, 64, 12h
 
# Do Router Advertisements, BUT NOT DHCP for this subnet.
#dhcp-range=1234::, ra-only 
 
# Do Router Advertisements, BUT NOT DHCP for this subnet, also try and
# add names to the DNS for the IPv6 address of SLAAC-configured dual-stack 
# hosts. Use the DHCPv4 lease to derive the name, network segment and 
# MAC address and assume that the host will also have an
# IPv6 address calculated using the SLAAC alogrithm.
#dhcp-range=1234::, ra-names
 
# Do Router Advertisements, BUT NOT DHCP for this subnet.
# Set the lifetime to 46 hours. (Note: minimum lifetime is 2 hours.)
#dhcp-range=1234::, ra-only, 48h
 
# Do DHCP and Router Advertisements for this subnet. Set the A bit in the RA
# so that clients can use SLAAC addresses as well as DHCP ones.
#dhcp-range=1234::2, 1234::500, slaac
 
# Do Router Advertisements and stateless DHCP for this subnet. Clients will
# not get addresses from DHCP, but they will get other configuration information.
# They will use SLAAC for addresses.
#dhcp-range=1234::, ra-stateless
 
# Do stateless DHCP, SLAAC, and generate DNS names for SLAAC addresses
# from DHCPv4 leases.
#dhcp-range=1234::, ra-stateless, ra-names
 
# Do router advertisements for all subnets where we're doing DHCPv6
# Unless overriden by ra-stateless, ra-names, et al, the router 
# advertisements will have the M and O bits set, so that the clients
# get addresses and configuration from DHCPv6, and the A bit reset, so the 
# clients don't use SLAAC addresses.
#enable-ra
 
# Supply parameters for specified hosts using DHCP. There are lots
# of valid alternatives, so we will give examples of each. Note that
# IP addresses DO NOT have to be in the range given above, they just
# need to be on the same network. The order of the parameters in these
# do not matter, it's permissible to give name, address and MAC in any
# order.
 
 
############
############ настройки DHCP - статические адреса
############
 
#выдать назначенному MAC, имя, IP,время аренды
dhcp-host=00:01:02:03:04:05,PC1,192.168.0.2,48h
dhcp-host=00:01:02:03:04:06,PC2,192.168.0.3,48h
 
# Always set the name of the host with hardware address
# 11:22:33:44:55:66 to be "fred"
#dhcp-host=11:22:33:44:55:66,fred
 
 
# Give a host with Ethernet address 11:22:33:44:55:66 or
# 12:34:56:78:90:12 the IP address 192.168.0.60. Dnsmasq will assume
# that these two Ethernet interfaces will never be in use at the same
# time, and give the IP address to the second, even if it is already
# in use by the first. Useful for laptops with wired and wireless
# addresses.
#dhcp-host=11:22:33:44:55:66,12:34:56:78:90:12,192.168.0.60
 
# Give the machine which says its name is "bert" IP address
# 192.168.0.70 and an infinite lease
#dhcp-host=bert,192.168.0.70,infinite
 
# Always give the host with client identifier 01:02:02:04
# the IP address 192.168.0.60
#dhcp-host=id:01:02:02:04,192.168.0.60
 
# Always give the host with client identifier "marjorie"
# the IP address 192.168.0.60
#dhcp-host=id:marjorie,192.168.0.60
 
# Enable the address given for "judge" in /etc/hosts
# to be given to a machine presenting the name "judge" when
# it asks for a DHCP lease.
#dhcp-host=judge
 
# Never offer DHCP service to a machine whose Ethernet
# address is 11:22:33:44:55:66
#dhcp-host=11:22:33:44:55:66,ignore
 
# Ignore any client-id presented by the machine with Ethernet
# address 11:22:33:44:55:66. This is useful to prevent a machine
# being treated differently when running under different OS's or
# between PXE boot and OS boot.
#dhcp-host=11:22:33:44:55:66,id:*
 
# Send extra options which are tagged as "red" to
# the machine with Ethernet address 11:22:33:44:55:66
#dhcp-host=11:22:33:44:55:66,set:red
 
# Send extra options which are tagged as "red" to
# any machine with Ethernet address starting 11:22:33:
#dhcp-host=11:22:33:*:*:*,set:red
 
# Give a fixed IPv6 address and name to client with 
# DUID 00:01:00:01:16:d2:83:fc:92:d4:19:e2:d8:b2
# Note the MAC addresses CANNOT be used to identify DHCPv6 clients.
# Note also the they [] around the IPv6 address are obilgatory.
#dhcp-host=id:00:01:00:01:16:d2:83:fc:92:d4:19:e2:d8:b2, fred, [1234::5] 
 
# Ignore any clients which are not specified in dhcp-host lines
# or /etc/ethers. Equivalent to ISC "deny unknown-clients".
# This relies on the special "known" tag which is set when
# a host is matched.
#dhcp-ignore=tag:!known
 
# Send extra options which are tagged as "red" to any machine whose
# DHCP vendorclass string includes the substring "Linux"
#dhcp-vendorclass=set:red,Linux
 
# Send extra options which are tagged as "red" to any machine one
# of whose DHCP userclass strings includes the substring "accounts"
#dhcp-userclass=set:red,accounts
 
# Send extra options which are tagged as "red" to any machine whose
# MAC address matches the pattern.
#dhcp-mac=set:red,00:60:8C:*:*:*
 
# 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
 
# Send options to hosts which ask for a DHCP lease.
# See RFC 2132 for details of available options.
# Common options can be given to dnsmasq by name:
# run "dnsmasq --help dhcp" to get a list.
# Note that all the common settings, such as netmask and
# broadcast address, DNS server and default route, are given
# sane defaults by dnsmasq. You very likely will not need
# any dhcp-options. If you use Windows clients and Samba, there
# are some options which are recommended, they are detailed at the
# end of this section.
 
# Override the default route supplied by dnsmasq, which assumes the
# router is the same machine as the one running dnsmasq.
#dhcp-option=3,1.2.3.4
 
# Do the same thing, but using the option name
#dhcp-option=option:router,1.2.3.4
 
# Override the default route supplied by dnsmasq and send no default
# route at all. Note that this only works for the options sent by
# default (1, 3, 6, 12, 28) the same line will send a zero-length option
# for all other option numbers.
#dhcp-option=3
 
# Set the NTP time server addresses to 192.168.0.4 and 10.10.0.5
#dhcp-option=option:ntp-server,192.168.0.4,10.10.0.5
 
# Send DHCPv6 option. Note [] around IPv6 addresses.
#dhcp-option=option6:dns-server,[1234::77],[1234::88]
 
# Send DHCPv6 option for namservers as the machine running 
# dnsmasq and another.
#dhcp-option=option6:dns-server,[::],[1234::88]
 
# Set the NTP time server address to be the same machine as
# is running dnsmasq
#dhcp-option=42,0.0.0.0
 
# Set the NIS domain name to "welly"
#dhcp-option=40,welly
 
# Set the default time-to-live to 50
#dhcp-option=23,50
 
# Set the "all subnets are local" flag
#dhcp-option=27,1
 
# Send the etherboot magic flag and then etherboot options (a string).
#dhcp-option=128,e4:45:74:68:00:00
#dhcp-option=129,NIC=eepro100
 
# Specify an option which will only be sent to the "red" network
# (see dhcp-range for the declaration of the "red" network)
# Note that the tag: part must precede the option: part.
#dhcp-option = tag:red, option:ntp-server, 192.168.1.1
 
# The following DHCP options set up dnsmasq in the same way as is specified
# for the ISC dhcpcd in
# http://www.samba.org/samba/ftp/docs/textdocs/DHCP-Server-Configuration.txt
# adapted for a typical dnsmasq installation where the host running
# dnsmasq is also the host running samba.
# you may want to uncomment some or all of them if you use
# Windows clients and Samba.
#dhcp-option=19,0           # option ip-forwarding off
#dhcp-option=44,0.0.0.0     # set netbios-over-TCP/IP nameserver(s) aka WINS server(s)
#dhcp-option=45,0.0.0.0     # netbios datagram distribution server
#dhcp-option=46,8           # netbios node type
 
# Send an empty WPAD option. This may be REQUIRED to get windows 7 to behave.
#dhcp-option=252,"\n"
 
# Send RFC-3397 DNS domain search DHCP option. WARNING: Your DHCP client
# probably doesn't support this......
#dhcp-option=option:domain-search,eng.apple.com,marketing.apple.com
 
# Send RFC-3442 classless static routes (note the netmask encoding)
#dhcp-option=121,192.168.1.0/24,1.2.3.4,10.0.0.0/8,5.6.7.8
 
# Send vendor-class specific options encapsulated in DHCP option 43.
# The meaning of the options is defined by the vendor-class so
# options are sent only when the client supplied vendor class
# matches the class given here. (A substring match is OK, so "MSFT"
# matches "MSFT" and "MSFT 5.0"). This example sets the
# mtftp address to 0.0.0.0 for PXEClients.
#dhcp-option=vendor:PXEClient,1,0.0.0.0
 
# Send microsoft-specific option to tell windows to release the DHCP lease
# when it shuts down. Note the "i" flag, to tell dnsmasq to send the
# value as a four-byte integer - that's what microsoft wants. See
# http://technet2.microsoft.com/WindowsServer/en/library/a70f1bb7-d2d4-49f0-96d6-4b7414ecfaae1033.mspx?mfr=true
#dhcp-option=vendor:MSFT,2,1i
 
# Send the Encapsulated-vendor-class ID needed by some configurations of
# Etherboot to allow is to recognise the DHCP server.
#dhcp-option=vendor:Etherboot,60,"Etherboot"
 
# Send options to PXELinux. Note that we need to send the options even
# though they don't appear in the parameter request list, so we need
# to use dhcp-option-force here.
# See http://syslinux.zytor.com/pxe.php#special for details.
# Magic number - needed before anything else is recognised
#dhcp-option-force=208,f1:00:74:7e
# Configuration file name
#dhcp-option-force=209,configs/common
# Path prefix
#dhcp-option-force=210,/tftpboot/pxelinux/files/
# Reboot time. (Note 'i' to send 32-bit value)
#dhcp-option-force=211,30i
 
# Set the boot filename for netboot/PXE. You will only need
# this is you want to boot machines over the network and you will need
# a TFTP server; either dnsmasq's built in TFTP server or an
# external one. (See below for how to enable the TFTP server.)
#dhcp-boot=pxelinux.0
 
# The same as above, but use custom tftp-server instead machine running dnsmasq
#dhcp-boot=pxelinux,server.name,192.168.1.100
 
# Boot for Etherboot gPXE. The idea is to send two different
# filenames, the first loads gPXE, and the second tells gPXE what to
# load. The dhcp-match sets the gpxe tag for requests from gPXE.
#dhcp-match=set:gpxe,175 # gPXE sends a 175 option.
#dhcp-boot=tag:!gpxe,undionly.kpxe
#dhcp-boot=mybootimage
 
# Encapsulated options for Etherboot gPXE. All the options are
# encapsulated within option 175
#dhcp-option=encap:175, 1, 5b         # priority code
#dhcp-option=encap:175, 176, 1b       # no-proxydhcp
#dhcp-option=encap:175, 177, string   # bus-id
#dhcp-option=encap:175, 189, 1b       # BIOS drive code
#dhcp-option=encap:175, 190, user     # iSCSI username
#dhcp-option=encap:175, 191, pass     # iSCSI password
 
# Test for the architecture of a netboot client. PXE clients are
# supposed to send their architecture as option 93. (See RFC 4578)
#dhcp-match=peecees, option:client-arch, 0 #x86-32
#dhcp-match=itanics, option:client-arch, 2 #IA64
#dhcp-match=hammers, option:client-arch, 6 #x86-64
#dhcp-match=mactels, option:client-arch, 7 #EFI x86-64
 
# Do real PXE, rather than just booting a single file, this is an
# alternative to dhcp-boot.
#pxe-prompt="What system shall I netboot?"
# or with timeout before first available action is taken:
#pxe-prompt="Press F8 for menu.", 60
 
# Available boot services. for PXE.
#pxe-service=x86PC, "Boot from local disk"
 
# Loads <tftp-root>/pxelinux.0 from dnsmasq TFTP server.
#pxe-service=x86PC, "Install Linux", pxelinux
 
# Loads <tftp-root>/pxelinux.0 from TFTP server at 1.2.3.4.
# Beware this fails on old PXE ROMS.
#pxe-service=x86PC, "Install Linux", pxelinux, 1.2.3.4
 
# Use bootserver on network, found my multicast or broadcast.
#pxe-service=x86PC, "Install windows from RIS server", 1
 
# Use bootserver at a known IP address.
#pxe-service=x86PC, "Install windows from RIS server", 1, 1.2.3.4
 
# If you have multicast-FTP available,
# information for that can be passed in a similar way using options 1
# to 5. See page 19 of
# http://download.intel.com/design/archives/wfm/downloads/pxespec.pdf
 
 
# Enable dnsmasq's built-in TFTP server
#enable-tftp
 
# Set the root directory for files available via FTP.
#tftp-root=/var/ftpd
 
# Make the TFTP server more secure: with this set, only files owned by
# the user dnsmasq is running as will be send over the net.
#tftp-secure
 
# This option stops dnsmasq from negotiating a larger blocksize for TFTP
# transfers. It will slow things down, but may rescue some broken TFTP
# clients.
#tftp-no-blocksize
 
# Set the boot file name only when the "red" tag is set.
#dhcp-boot=net:red,pxelinux.red-net
 
# An example of dhcp-boot with an external TFTP server: the name and IP
# address of the server are given after the filename.
# Can fail with old PXE ROMS. Overridden by --pxe-service.
#dhcp-boot=/var/ftpd/pxelinux.0,boothost,192.168.0.3
 
# If there are multiple external tftp servers having a same name
# (using /etc/hosts) then that name can be specified as the
# tftp_servername (the third option to dhcp-boot) and in that
# case dnsmasq resolves this name and returns the resultant IP
# addresses in round robin fasion. This facility can be used to
# load balance the tftp load among a set of servers.
#dhcp-boot=/var/ftpd/pxelinux.0,boothost,tftp_server_name
 
 
 
# Run an executable when a DHCP lease is created or destroyed.
# The arguments sent to the script are "add" or "del",
# then the MAC address, the IP address and finally the hostname
# if there is one.
#dhcp-script=/bin/echo
 
 
 
# Normally responses which come form /etc/hosts and the DHCP lease
# file have Time-To-Live set as zero, which conventionally means
# do not cache further. If you are happy to trade lower load on the
# server for potentially stale date, you can set a time-to-live (in
# seconds) here.
#local-ttl=
 
# If you want dnsmasq to detect attempts by Verisign to send queries
# to unregistered .com and .net hosts to its sitefinder service and
# have dnsmasq instead return the correct NXDOMAIN response, uncomment
# this line. You can add similar lines to do the same for other
# registries which have implemented wildcard A records.
#bogus-nxdomain=64.94.110.11
 
# If you want to fix up DNS results from upstream servers, use the
# alias option. This only works for IPv4.
# This alias makes a result of 1.2.3.4 appear as 5.6.7.8
#alias=1.2.3.4,5.6.7.8
# and this maps 1.2.3.x to 5.6.7.x
#alias=1.2.3.0,5.6.7.0,255.255.255.0
# and this maps 192.168.0.10->192.168.0.40 to 10.0.0.10->10.0.0.40
#alias=192.168.0.10-192.168.0.40,10.0.0.0,255.255.255.0
 
# Change these lines if you want dnsmasq to serve MX records.
 
# Return an MX record named "maildomain.com" with target
# servermachine.com and preference 50
#mx-host=maildomain.com,servermachine.com,50
 
# Set the default target for MX records created using the localmx option.
#mx-target=servermachine.com
 
# Return an MX record pointing to the mx-target for all local
# machines.
#localmx
 
# Return an MX record pointing to itself for all local machines.
#selfmx
 
# Change the following lines if you want dnsmasq to serve SRV
# records.  These are useful if you want to serve ldap requests for
# Active Directory and other windows-originated DNS requests.
# See RFC 2782.
# You may add multiple srv-host lines.
# The fields are <name>,<target>,<port>,<priority>,<weight>
# If the domain part if missing from the name (so that is just has the
# service and protocol sections) then the domain given by the domain=
# config option is used. (Note that expand-hosts does not need to be
# set for this to work.)
 
# A SRV record sending LDAP for the example.com domain to
# ldapserver.example.com port 389
#srv-host=_ldap._tcp.example.com,ldapserver.example.com,389
 
# A SRV record sending LDAP for the example.com domain to
# ldapserver.example.com port 389 (using domain=)
#domain=example.com
#srv-host=_ldap._tcp,ldapserver.example.com,389
 
# Two SRV records for LDAP, each with different priorities
#srv-host=_ldap._tcp.example.com,ldapserver.example.com,389,1
#srv-host=_ldap._tcp.example.com,ldapserver.example.com,389,2
 
# A SRV record indicating that there is no LDAP server for the domain
# example.com
#srv-host=_ldap._tcp.example.com
 
# The following line shows how to make dnsmasq serve an arbitrary PTR
# record. This is useful for DNS-SD. (Note that the
# domain-name expansion done for SRV records _does_not
# occur for PTR records.)
#ptr-record=_http._tcp.dns-sd-services,"New Employee Page._http._tcp.dns-sd-services"
 
# Change the following lines to enable dnsmasq to serve TXT records.
# These are used for things like SPF and zeroconf. (Note that the
# domain-name expansion done for SRV records _does_not
# occur for TXT records.)
 
#Example SPF.
#txt-record=example.com,"v=spf1 a -all"
 
#Example zeroconf
#txt-record=_http._tcp.example.com,name=value,paper=A4
 
# Provide an alias for a "local" DNS name. Note that this _only_ works
# for targets which are names from DHCP or /etc/hosts. Give host
# "bert" another name, bertrand
#cname=bertand,bert
 
#включить отладочный лог 
#log-queries
 
# логировать максимум информации
#log-dhcp
#в какой файл сваливать лог, иначе буде тощий системный лог
log-facility=/var/log/dnsmasq.log
 
#добавить файл конфигурации dnsmasq.more.conf к настройкам (строк может быть >1)
#conf-file=/etc/dnsmasq.more.conf
#добавить настройки из всех файлов,находящихся по умолчанию в папке /etc/dnsmasq/conf.d, кроме файлов .bak, а также заканчивающихся символом ~, либо начинающиеся с ”.”, либо начинающиеся и заканчивающиеся символом # пропускаются всегда:
#conf-dir=/etc/dnsmasq.d

Запуск службы:

service dnsmasq start

F.A.Q. Параметр authoritativehttp://samag.ru/archive/article/2085) позволяет объявить сервер авторитативным (ответственным) в обслуживаемой сети. Отличие авторитативного сервера от «обычного» заключается в том, что последний игнорирует любые запросы адресов, которые не описаны в его конфигурации, в то время как авторитативный сервер в ответ на такие запросы отсылает DHCPNAK. Благодаря такому поведению клиент, перемещённый из другой подсети, сможет быстрее получить новый адрес (в ответ на DHCPREQUEST с адресом из прежней подсети он сразу получит DHCPNAK и приступит к получению нового адреса; в противном случае DHCPDISCOVER будет отправлен лишь по истечении тайм-аута на ожидание ответа). В то же время «случайные» DHCP-серверы (например, ошибочно запущенные с настройками из файла-примера) с меньшей вероятностью смогут помешать работе сети, поскольку, будучи неавторитативными, будут просто игнорировать «чужие» запросы DHCPREQUEST.

linux/dnsmasq.txt · Последнее изменение: 2020/07/02 11:25 — adminroot