94 lines
2.0 KiB
Markdown
94 lines
2.0 KiB
Markdown
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---
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title: 'DHCP Server and Routing'
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---
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## Installation
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`# apt install isc-dhcp-server`
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## Configuration
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Edit `/etc/default/isc-dhcp-server`
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`INTERFACESv4="(interface 1) (interface 2)"`
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Edit `/etc/dhcp/dhcpd.conf` to set a subnet
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```
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subnet (netaddress) netmask (subnetmask) {
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range (first dhcp) (last dhcp);
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option subnet-mask (subnetmask);
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option routers (gateway);
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option domain-name "(name)";
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option domain-name-servers (dns server);
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}
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```
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Edit `/etc/network/interfaces`
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```
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auto (interface)
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iface (interface) inet static
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address (address)
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network (netaddress)
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netmask (netmask)
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broadcast (broadcast)
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```
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Enable the interface
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`# ifup (interface)`
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Restart DHCP Server
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`# systemctl restart isc-dhcp-server.service`
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### Enable routing
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`# echo "net.ipv4.ip_forward=1" >> /etc/sysctl.d/80-forwarding.conf`
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`# sysctl -p /etc/sysctl.d/80-forwarding.conf`
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`# iptables -t nat -A POSTROUTING -o (WAN interface) -j MASQUERADE`
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`# iptables -A FORWARD -i (LAN interface) -j ACCEPT`
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Make iptables permanent
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Select `Yes` during the installation to save current rules
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`# apt install iptables-persistent`
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### Enable DHCP-managed fixed IP address
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```
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host (hostname) {
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hardware ethernet (mac);
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fixed-address (ip address);
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}
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```
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### Dynamic DNS
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*Needs a supported DNS like BIND or PowerDNS*
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[Configure your DNS server to accept updates](https://wiki.realstickman.net/e/en/linux/services/powerdns)
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Add the following snippet to your `/etc/dhcp/dhcpd.conf` file
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How to generate the key is also described in the DNS article
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```
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ddns-updates on;
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ddns-update-style interim;
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update-static-leases on;
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ddns-domainname "testpdns";
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ddns-rev-domainname "in-addr.arpa.";
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key "(keyname)" {
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algorithm hmac-md5;
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secret "(key)";
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};
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zone testpdns {
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primary 127.0.0.1;
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key (keyname);
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}
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zone 7.168.192.in-addr.arpa. {
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primary 127.0.0.1;
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key (keyname);
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}
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```
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## Client
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DHCP Request
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`# dhclient -v`
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Release IP
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`# dhclient -v -r`
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