WeOSInterface
Introduction
A network interface handles configuration of the network layer in a computer network. It can be a representation of a hardware unit but it also be a pure software construction in case of a SSL interface or a loopback interface. It typically has a network address.
Overview
In its simplest case a interface is a higher layer representation of a network port in a 1-1 mapping. A more complex example is a VLAN interface that can contain several network ports. It handles the network layer which means it typically has a network address such as an IPV4 address. It also resolves mapping between network addresses and MAC addresses through ARP functionality.
For the image below two hosts are connected via ports eth1 on each unit. Host-1 have configured interface vlan1 with address 192.168.0.10/24 and Host-2 have configured vlan2 with address 192.168.0.20/24.
Host-1 Host-2
.-------. .-------.
| | | |
| | | |
| 1 |vlan1 vlan2| 1 |
'---+---' '---+---'
|.10 192.168.0.0/24 .20|
+-----------------------------------------------+
Configuration
Configuration of network interfaces is done in the iface context. Note that there are several configurable options which may not be relevant for each interface type. A custom MAC address and configuration options with respect to ARP are only relevant for interfaces which have a MAC address (LAN interfaces).
Example of how to configure interface vlan1:
example:/#> configure example:/config/#> iface vlan1 example:/config/iface-vlan1/#>
On VLAN interfaces, it is possible to circumvent the link status propagation property by configuring an interface as always up:
example:/config/iface-vlan1/#> enable always
However, disabling link status propagation may significantly impact layer-3 protocols such as RIP, OSPF, VRRP, and more. The protocols will have to fall-back to other methods to detect link-down, e.g. hello message timeout and similar.
Do not use the enable always setting unless you really know what you are doing.
Syntax
[no|show] inet [static IP/LEN|dhcp|ssl|link-local|ttdp]-
This setting controls the handling of network addresses. It can be set and/or acquired in several ways.
Note
Enters a sub-configuration context for any inet specific settings.
- no
- No network address will be set
- static IP/LEN
- Configure a static [IP] address with network mask with length [LEN]
- dhcp
- Acquire a network address through the DHCP protocol
- ssl
- Acquire a network address through the SSL protocol
- link-local
- Acquire a network address through the link-local protocol
- ttdp
- Acquire a network address through the TTDP protocol
[no|show] inet6 [static IP/LEN [eui-64] | link-local]-
This settings controls how IPv6 addresses can be configured on the interface. Currently only static and link-local address methods are supported for IPv6 address configuration.
Note
For the IPv6 address to be added to the interface, global IPv6 functionality must be enabled on the device. This is done by enabling the global IPv6 functionality in the IPv6 configuration context. The below example is how it is done in the CLI:
example:/#> configure example:/config/#> ipv6 example:/config/ipv6/#> enable
Note
Enters a sub-configuration context for any inet6 settings that may be specific to the selected method.
Examples Configuring a static IPv6 address:
example:/config/iface-vlan1/#> inet6 static 2001:db8::1234:5678/64
Configuring a link-local IPv6 address:
example:/config/iface-vlan1/#> inet6 link-local
- no
- Remove configured IPv6 address method. If no specific inet6 method is specified, all configured IPv6 address methods will be removed.
- static IP/LEN [eui-64]
-
Configure a static
IPaddress with network mask with lengthLEN.If no
LENis provided, the default length of /64 will be used.The optional
eui-64keyword can be used to enable EUI-64 address generation for the interface. The eui-64 address generation is based on the MAC address of the interface. The MAC address is split in half, and the 7th bit is flipped. The resulting half MAC address is then inserted in the middle of the IPv6 address. The initial part of the IPv6 address is taken from the provided static IP address.As en example, if the initial part of the provided IPv6 address is 2001:db8:8888:9999 and the MAC address of the interface is 00:11:22:33:44:55, the resulting IPv6 address will be 2001:db8:8888:9999:211:22ff:fe33:4455/64. This is how it would be configured in the CLI:
example:/config/iface-vlan1/#> inet6 static 2001:db8:8888:9999::/64 eui-64
- link-local
-
Specify that the interface should acquire a link-local IPv6 address.
The link-local address is based on the MAC address of the interface. If the MAC address of the interface is 00:11:22:33:44:55, the resulting link-local address will be fe80::211:22ff:fe33:4455/64.
Note
Regardless of the selected IPv6 address method, the link-local address will always be enabled, even if it is not explicitly configured. The reason for this is that the link-local address is always required for IPv6 communication.
[no] enable [always]-
This setting controls the administrative state for the interface, if it should be UP or DOWN.
Note
If the interface is a VLAN interface and it is disabled, the CPU connection to that VLAN is also completely severed. Only layer-2 switching will work on this VLAN, while all layer-3 services such as management, routing, firewall, etc. will be disabled.
If the intention is to disable the entire VLAN itself, that action is performed in the VLAN configuration context.
Warning
Disabling an interface may cause loss of connectivity to the device, which may require physical access to the device to restore connectivity. Be mindful of which interface, you may potentially be accessing the device over.
- no
- Administratively disable the interface.
- always
-
When set, the interface will remain up even if the link is down.
Note
This setting only available for VLAN interfaces.
[no] shutdown-
Shutdown the interface, same as “no up”
- no
- Enable interface
[no] mac [MAC]-
Change or restore MAC address of interface.
- no
- Use default MAC address
[no] mtu [68-1500]-
Set maximum transfer unit, MTU, of interface.
- no
- Use default MTU size
[no] redirect-
Enable sending of ICMP redirect messages.
- no
- Disable sending of ICMP redirect messages
[no] proxy-arp-
Control Proxy ARP on this interface.
- no
- Default disable proxy ARP on this interface
[no] arp-notify-
Control gratuitous ARP on link up and address change.
- no
- Default disable gratuitous ARP on this interface
[no] arp-accept-
Allow receiving gratuitous ARP on this interface.
- no
- Default disable receiving gratuitous ARP on this interface
[no] name-
This setting controls the interface name.
- no
- Default name used for this interface
[no] distance [1-255] [track TRIGGER-ID]-
Administrative distance for routes learned on this interface.
Static routes learned dynamically, e.g. via DHCP, will be installed in the routing table with this administrative distance.
Possible values are 1-255, where 1 is the best and 255 is infinity, it will be visible in the routing table but will never be activated.
Use the form ‘no distance’ to reset the value to its default value, 16. Use ‘distance 255’ to prevent routes from ever being activated.
A ping trigger can be associated with the interface distance setting. In case of connectivity loss, the distance of the associated route (s) are raised to infinity (255)
- no
- Use default distance for this interface (16)
show-
Show the summary for the configuration of the interface, an example is shown below.
Name : vlan1 Admin Mode : Up MAC Address : AUTO IP Addresses : Inet link-local Inet static 192.168.2.10/24 MTU : AUTO (1500) ICMP Redirect : Sending Proxy ARP : Disabled ARP Notify : Enabled ARP Accept : Enabled Distance : 1
Inet DHCP Configuration
DHCP client configuration is performed in a sub-context under the interface configuration:
example:/config/iface-vlan1/#> inet dhcp example:/config/iface-vlan1/inet-dhcp/#>
[no] clientid <hex|string> <STRING>-
Configure the Client ID that is sent in DHCP requests.
Default: Use mac address.
- no
- Remove the configured client-id and use the default value.
- hex
- Indicates that the subsequent value is provided in hexadecimal form. The
following syntax forms are valid:
0x1a2b,1a:2b,1a2b. - string
- Indicates that the subsequent value is provided in string format.
[no] arping-
Enable ARP-ping option in DHCP client.
- no
- Disable ARP-ping option in DHCP client.
Default: Enabled
[no] option <OPT> [<OPT>...]-
Configure the DHCP Parameter Request List (DHCP option 55) that the client provides in its communication with the server.
The system supports the following options to be included in the DHCP Parameter Request List:
Option Number Description Requested by Default 1 Subnet Yes 3 Router Yes 6 DNS Server Yes 7 Log Server Yes 12 Hostname Yes 15 Domain Yes 42 NTP Server Yes 66 TFTP Server - 67 Bootfile - 121 Classless Route Yes 249 Microsoft Classless Route Yes Note
Only the options that are explicitly requested will be used and applied on the device. In other words, if a DHCP server provides any of these options anyway, when it was not included as part of the client’s Parameter Request List, the client will ignore those options.
DHCP Option 249 is a Microsoft specific variant of option 121. If both 121 and 249 are received as part of a lease, and their contents are identical, only one copy of the relevant routes will be installed on the client. If their content differ, their union will be installed. System administrators should ensure routes advertised by options 121 and 249 are identical.
If DHCP Classless static route option (121 and/or 249) is configured on the WeOS DHCP client, then option 3 should also be configured. If the server provides option 121/249 in its response, it will be used by the client and any response to option 3 will be ignored.
- no
-
Use
no optionto reset the option request to the default options. Useno option OPTto not request that specific option.Note
If all specific option requests are removed no Parameter Request List will be included as part of the client’s requests, i.e. there is no implicit Parameter Request List (option 55) included from the client.
In this scenario the DHCP client will apply any option it may support, if it is provided by the lease from the DHCP server.
- OPT
- DHCP option number.
Examples
The factory configuration for a standard interface will be configured to acquire network address through DHCP and link-local address protocols. For the example below, we will configure the two host with static network addresses and link-local addresses also.
Use case with static address
Two network units are connected via a network cable on port 1 on both hosts. Per default when a DHCP server isn’t present on the network the hosts will only acquire a link link address in the 169.254.0.0/16 range. In this case we want to set fixed addresses on both host in the 192.168.0.0/24 range. We’ll also use link local addresses on both hosts.
Host-1 Host-2
.-------. .-------.
| | | |
| | | |
| 1 |vlan1 vlan1| 1 |
'---+---' '---+---'
|.10 192.168.0.0/24 .20|
+-----------------------------------------------+
Configuration for Host-1Host-1:/#> configure Host-1:/config/#> iface vlan1 Host-1:/config/iface-vlan1/#> inet static 192.168.2.10/24 Host-1:/config/iface-vlan1/inet-static-192.168.2.10/#> exit Host-1:/config/iface-vlan1/#> inet link-local Host-1:/config/iface-vlan1/inet-link-local#> leave
Configuration for Host-2Host-2:/#> configure Host-2:/config/#> iface vlan1 Host-2:/config/iface-vlan1/#> inet static 192.168.2.20/24 Host-2:/config/iface-vlan1/inet-static-192.168.2.20/#> exit Host-2:/config/iface-vlan1/#> inet link-local Host-2:/config/iface-vlan1/inet-link-local#> leave
Use case in DHCP Client mode
Two network units are connected via a network cable on port 1 on both hosts. The Host-2 runs a DHCP server with subnet range 192.168.1.0. The DHCP-Server has in this case an address pool in the range of 192.168.1.100 and 192.168.1.199. The Host-1 is configured to use inet dhcp on vlan1. We’ll also use link local address.
Host-1 Host-2
.-------. .-------.
| DHCP | | DHCP |
| Client| | Server|
| 1 |vlan1 vlan1| 1 |
'---+---' '---+---'
| dhcp .100 192.168.1.0/24 .1|
+-----------------------------------------------+
pool 192.168.1.100-199
Configuration for Host-1Host-1:/#> configure Host-1:/config/#> iface vlan1 Host-1:/config/iface-vlan1/#> inet dhcp Host-1:/config/iface-vlan1/inet-dhcp/#> exit Host-1:/config/iface-vlan1/#> inet link-local Host-1:/config/iface-vlan1/inet-link-local#> leave
Configuration for Host-2example:/#> configure example:/config/#> dhcp-server example:/config/dhcp-server/#> subnet 192.168.1.0/24 Created new DHCP server for subnet 192.168.1.0. example:/config/dhcp-server/subnet-192.168.1.0/#> example:/config/dhcp-server/subnet-192.168.1.0/#>pool 192.168.1.50 192.168.1.99 example:/config/dhcp-server/subnet-192.168.1.0/#>leave
for more information see * DHCP-Server/Configuration
Status Overview
In order to verify an interface’s setting the ‘show’ command can be used:
Host-1:/#> show iface vlan1
Name : vlan1
Admin. State : Up
Oper. Status : UP
MAC Address : 52:54:00:12:34:56
IP Addresses : 192.168.2.10/24 (static)
169.254.81.131/16 (link-local)
MTU : 1500
Statistics :
RX: Packets Bytes Errors CsumErrs OutOfSeq Mcasts
57 4621 0 0 0 15
TX: Packets Bytes Errors DeadLoop NoRoute NoBufs
164 29003 0 0 0 0
This show that the interface vlan1 on Host-1 is up. It has two network addresses, 192.168.2.10/24 which has been configured as static and also network address 169.254.81.131/16 which has been resolved through link-local addressing.