Linux/Netzwerk/Konfiguration

Linux/Netzwerk/Konfiguration

Beschreibung

Tipp

Bezüglich einer aktuellen Anleitung für Debian zum Thema Netzwerk lesen Sie Debian Administratorhandbuch — Konfigurieren des Netzwerks

Tipp

Unter systemd kann networkd für die Netzwerkverwaltung genutzt werden

• siehe systemd-networkd(8)

/etc/network/interfaces

siehe /etc/network/interfaces

3 ways to configure the network

1. The interfaces configuration file at /etc/network/interfaces (this page): for basic or simple configurations (e.g. workstation)
2. NetworkManager: This is the default for Laptop configuration
3. Systemd: Debian reference Doc Chapter 5

vlan

Howto use vlan (dot1q, 802.1q, trunk)

Manual config

modprobe 8021q

apt install vlan

vconfig add eth0 222 # 222 is vlan number
ifconfig eth0.222 up
ifconfig eth0.222 mtu 1496 #optional if your network card doesn't support MTU 1504B
ifconfig eth0.222 10.10.10.1 netmask 255.255.255.0

Network init script config

Into /etc/modules add line:

8021q

In /etc/network/interfaces to section iface add parameter:

vlan-raw-device eth0

The interface name should be the raw interface name (the same as specified by vlan-raw-device), then a dot, then the VLAN ID, for example eth0.100. It can instead be "vlan" then the VLAN ID, for example vlan100. In either case, the VLAN ID is on the end, and this is the only place that it is configured.

Note: If you name your VLAN interfaces ethX.YYY, then there is no need to specify the vlan-raw-device, as the raw device can be retrieved from the interface name.

Eg:

auto eth0.222
iface eth0.222 inet static
 address 10.10.10.1/24
 vlan-raw-device eth0

Bridges and VLANs

If you create VLAN interfaces only to put them into a bridge, there is no need to define the VLAN interfaces manually. Just config the bridge, and the VLAN interface will be created automatically when creating the bridge, e.g:

auto br1
iface br1 inet manual
 bridge_ports eth0.99 eth1.99
 up /usr/sbin/brctl stp br1 on

Caveats when using bridging and vlan

#/etc/network/interfaces
auto eth0 bri0
iface eth0 inet static
 address 192.168.1.1/24
iface eth0.110 inet manual
 vlan-raw-device eth0
iface bri0 inet static
 address 192.168.110.1/24
 bridge_ports eth0.110
 bridge_stp on
 bridge_maxwait 10

If you are using a brigded VLAN setup, which is probably useful for networking in virtualization environments, take care to only attach either a bridge device or VLAN devices to an underlying physical device - like shown above. Attaching the physical interface (eth0) to a bridge (eg. bri1) while using the same physical interface on apparently different VLANs will result in all packets to remain tagged. (Kernel newer than 2.6.37 and older than 3.2).

Howto create fault tolerant bonding with vlan (Etch - Stretch)

"debian_bonding.png"

debian_bonding.dia

How to configure one of the above server active backup bonding 3 vlan {vlan10,vlan20,vlan30} Debian networking without SPOF without native vlan.

aptitude install vlan ifenslave-2.6

Network config

Cisco switch interface example config

interface GigabitEthernet1/2
 description eth1
 switchport
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 10,20,30
 switchport mode trunk
 no ip address
 no cdp enable
 spanning-tree portfast trunk

bonding with active backup

Create a file /etc/modprobe.d/bonding.conf containing:

alias bond0 bonding
options bonding mode=active-backup miimon=100 downdelay=200 updelay=200 primary=eth1

/etc/network/interfaces

# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
auto bond0
iface bond0 inet manual
 up ifconfig bond0 0.0.0.0 up
 slaves eth1 eth0
auto vlan10
iface vlan10 inet static
 address 10.10.10.12/24
 vlan-raw-device bond0
 gateway 10.10.0.1
 dns-search hup.hu
 dns-nameservers 10.10.0.2
auto vlan20
iface vlan20 inet static
 address 10.20.10.12/24
 vlan-raw-device bond0
auto vlan30
iface vlan30 inet static
 address 10.30.10.12/24
 vlan-raw-device bond0

• In Debian Buster, you must use interface names for VLANs in the form of: bond0.10, bond0.20, and bond0.30 instead of vlan10, vlan20, vlan30
• https://www.kernel.org/doc/Documentation/networking/bonding.txt - Linux kernel documentation on bonding
• https://www.dm.unibo.it/~donatini/admin/rete/bonding.html - Bonding on Linux 2.6

How to set the MTU (Max transfer unit / packet size) with VLANS over a bonded interface

MTU needs to be configured on the bonding interface and slave interfaces after the reset of the configuration has been applied to the bonding interfaces. This is done using a post-up line in the bonding interface configuration.

auto bond0
iface bond0 inet manual
 up ifconfig lacptrunk0 0.0.0.0 up
 slaves eth0 eth1
# bond-mode 4 = 802.3ad
 bond-mode 4
 bond-miimon 100
 bond-downdelay 200
 bond-updelay 200
 bond-lacp-rate 1
 bond-xmit-hash-policy layer2+3
 post-up ifconfig eth0 mtu 9000 && ifconfig eth1 mtu 9000 && ifconfig bond0 mtu 9000

#vlan devices will use the MTU set on bond0 device
auto vlan101
iface vlan101 inet static

address 10.101.60.123/24
gateway 10.155.60.1
vlan-raw-device bond0

auto vlan151
iface vlan151 inet static

address 192.168.1.1/24
vlan-raw-device bond0

Multiple IP addresses on one Interface

Interface aliasing allows one interface to have multiple IP addresses. This is useful when more than one server is to be visible via the Internet. Note that virtual hosts can support multiple Apache servers with a single IP address. Apache responds to the domain name supplied by the client in the HTTP header. In many other situations, one external IP is needed for each server using a port.

Legacy method

This /etc/network/interfaces text assigns three IP addresses to eth0.

auto eth0
allow-hotplug eth0
iface eth0 inet static
 address 192.168.1.42/24
 gateway 192.168.1.1

auto eth0:0
allow-hotplug eth0:0
iface eth0:0 inet static
 address 192.168.1.43/24

auto eth0:1
allow-hotplug eth0:1
iface eth0:1 inet static
 address 192.168.1.44/24

An alias interface should not have "gateway" or "dns-nameservers"; dynamic IP assignment is permissible.

The above configuration is the previous traditional method that reflects the traditional use of ifconfig to configure network devices. ifconfig has introduced the concept of aliased or virtual interfaces. Those types of virtual interfaces have names of the form interface:integer and ifconfig treats them very similarly to real interfaces.

Nowadays ifupdown uses the ip utility from the iproute2 package instead of ifconfig. The newer ip utility does not use the same concept of aliases or virtual interfaces. However, it supports assigning arbitrary names to the interfaces (they're called labels). ifupdown uses this feature to support aliased interfaces while using ip.

iproute2 method

Also, ifupdown supports specifying multiple interfaces by repeating iface sections with the same interface name. The key difference from the method described above is that all such sections are treated by ifupdown as just one interface, so user can't add or remove them individually. However, up/down commands, as well as scripts, are called for every section as it used to be.

Note however that this method is dangerous! Certain driver/hardware combinations may sometimes fail to bring the link up if no labels are assigned to the alias interfaces. (Seen this on Debian Wheezy and Jessie with RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 01) auto-negotiating to 10/full. A similar warning from another person exists in the history of this page.)

This /etc/network/interfaces text assigns three IP addresses to eth0.

auto eth0
allow-hotplug eth0
iface eth0 inet static
 address 192.168.1.42/24
 gateway 192.168.1.1

iface eth0 inet static
 address 192.168.1.43/24

iface eth0 inet static
 address 192.168.1.44/24

# adding IP addresses from different subnets is also possible
iface eth0 inet static
 address 10.10.10.14/24

Manual approach:

auto eth0
allow-hotplug eth0
iface eth0 inet static
 address 192.168.1.42/24
 gateway 192.168.1.1
 up ip addr add 192.168.1.43/24 dev $IFACE label $IFACE:0
 down ip addr del 192.168.1.43/24 dev $IFACE label $IFACE:0
 up ip addr add 192.168.1.44/24 dev $IFACE label $IFACE:1
 down ip addr del 192.168.1.44/24 dev $IFACE label $IFACE:1
 up ip addr add 10.10.10.14/24 dev $IFACE label $IFACE:2
 down ip addr del 10.10.10.14/24 dev $IFACE label $IFACE:2

Quelle: https://wiki.debian.org/NetworkConfiguration