摘要
使用NanoPI创建UDHCP服务器
はじめに
NanoPIをRouterにする にて、1台のマシンをinternetに繋ぎ、その他のマシンをLANでせつぞくしてInternet接続を共有する方法を説明しました。
しかし「接続できる。」と「使える」には隔たりがあります。routeの設定、DNSの設定がなければ繋がっていても使えません。手動で各clientを設定することはできますが、手間なのでdhcp daemonを導入しましょう。
DHCPDの種類
dhcpdは一種類ではありません。
- isc-dhcp-daemon
- udhcpd
- dhcp3-server
などがあります。
NanoPI上でdeadwoodを動かすに書いたように、iscのソフトは一般的ですが、デカくて、重くて、バギーなのであまり好きになれません。今回はudhcpdを使ってみることにしました。
Install
Installはとっても簡単です。
apt update
apt upgrade
apt install udhcpd
設定
設定もとっても簡単です。
/etc/udhcpd.conf
# Sample udhcpd configuration file (/etc/udhcpd.conf)
# The start and end of the IP lease block
start 192.168.254.150 #default: 192.168.0.20
end 192.168.254.160 #default: 192.168.0.254
# The interface that udhcpd will use
interface eth0 #default: eth0
# The maximim number of leases (includes addressesd reserved
# by OFFER's, DECLINE's, and ARP conficts
max_leases 10 #default: 254
# If remaining is true (default), udhcpd will store the time
# remaining for each lease in the udhcpd leases file. This is
# for embedded systems that cannot keep time between reboots.
# If you set remaining to no, the absolute time that the lease
# expires at will be stored in the dhcpd.leases file.
# remaining yes #default: yes
# The time period at which udhcpd will write out a dhcpd.leases
# file. If this is 0, udhcpd will never automatically write a
# lease file. (specified in seconds)
# auto_time 7200 #default: 7200 (2 hours)
# The amount of time that an IP will be reserved (leased) for if a
# DHCP decline message is received (seconds).
# decline_time 3600 #default: 3600 (1 hour)
# The amount of time that an IP will be reserved (leased) for if an
# ARP conflct occurs. (seconds
# conflict_time 3600 #default: 3600 (1 hour)
# How long an offered address is reserved (leased) in seconds
# offer_time 60 #default: 60 (1 minute)
# If a lease to be given is below this value, the full lease time is
# instead used (seconds).
# min_lease 60 #defult: 60
# The location of the leases file
# lease_file /var/lib/misc/udhcpd.leases #defualt: /var/lib/misc/udhcpd.leases
# The location of the pid file
# pidfile /var/run/udhcpd.pid #default: /var/run/udhcpd.pid
# Everytime udhcpd writes a leases file, the below script will be called.
# Useful for writing the lease file to flash every few hours.
# notify_file #default: (no script)
# notify_file dumpleases # <--- useful for debugging
# The following are bootp specific options, setable by udhcpd.
# siaddr 192.168.0.22 #default: 0.0.0.0
# sname zorak #default: (none)
# boot_file /var/nfs_root #default: (none)
# The remainer of options are DHCP options and can be specifed with the
# keyword 'opt' or 'option'. If an option can take multiple items, such
# as the dns option, they can be listed on the same line, or multiple
# lines. The only option with a default is 'lease'.
# Examles
opt dns 192.168.254.80
option subnet 255.255.255.0
opt router 192.168.254.80
opt wins 192.168.10.10
option domain local
option lease 864000 # 10 days of seconds
# Currently supported options, for more info, see options.c
# opt subnet
# opt timezone
# opt router
# opt timesrv
# opt namesrv
# opt dns
# opt logsrv
# opt cookiesrv
# opt lprsrv
# opt bootsize
# opt domain
# opt swapsrv
# opt rootpath
# opt ipttl
# opt mtu
# opt broadcast
# opt wins
# opt lease
# opt ntpsrv
# opt tftp
# opt bootfile
# opt wpad
# Static leases map
# static_lease 00:60:08:11:CE:4E 192.168.0.54
# static_lease 00:60:08:11:CE:3E 192.168.0.44
再起動
設定したら再起動します。
systemctl restart udhcpd
結論
小型軽量の組込用に使いやすいdhcp daemonです。