MACVLAN - Pseudo Ethernet
Pseudo-Ethernet or MACVLAN interfaces can be seen as subinterfaces to regular ethernet interfaces. Each and every subinterface is created a different media access control (MAC) address, for a single physical Ethernet port. Pseudo- Ethernet interfaces have most of their application in virtualized environments,
By using Pseudo-Ethernet interfaces there will be less system overhead compared to running a traditional bridging approach. Pseudo-Ethernet interfaces can also be used to workaround the general limit of 4096 virtual LANs (VLANs) per physical Ethernet port, since that limit is with respect to a single MAC address.
Every Virtual Ethernet interfaces behaves like a real Ethernet interface. They can have IPv4/IPv6 addresses configured, or can request addresses by DHCP/ DHCPv6 and are associated/mapped with a real ethernet port. This also makes Pseudo-Ethernet interfaces interesting for testing purposes. A Pseudo-Ethernet device will inherit characteristics (speed, duplex, …) from its physical parent (the so called link) interface.
Once created in the system, Pseudo-Ethernet interfaces can be referenced in the exact same way as other Ethernet interfaces. Notes about using Pseudo- Ethernet interfaces:
Pseudo-Ethernet interfaces can not be reached from your internal host. This means that you can not try to ping a Pseudo-Ethernet interface from the host system on which it is defined. The ping will be lost.
Loopbacks occurs at the IP level the same way as for other interfaces, ethernet frames are not forwarded between Pseudo-Ethernet interfaces.
Pseudo-Ethernet interfaces may not work in environments which expect a NIC to only have a single address. This applies to: - VMware machines using default settings - Network switches with security settings allowing only a single MAC address - xDSL modems that try to learn the MAC address of the NIC
Configuration
Common interface configuration
Configure interface <interface> with one or more interface addresses.
address can be specified multiple times as IPv4 and/or IPv6 address, e.g. 192.0.2.1/24 and/or 2001:db8::1/64
dhcp interface address is received by DHCP from a DHCP server on this segment.
dhcpv6 interface address is received by DHCPv6 from a DHCPv6 server on this segment.
Example:
set interfaces pseudo-ethernet peth0 address 192.0.2.1/24
set interfaces pseudo-ethernet peth0 address 2001:db8::1/64
set interfaces pseudo-ethernet peth0 address dhcp
set interfaces pseudo-ethernet peth0 address dhcpv6
Set a human readable, descriptive alias for this connection. Alias is used by
e.g. the show interfaces command or SNMP based monitoring tools.
Example:
set interfaces pseudo-ethernet peth0 description 'This is an awesome interface running on VyOS'
Disable given <interface>. It will be placed in administratively down
(A/D) state.
Example:
set interfaces pseudo-ethernet peth0 disable
Ethernet flow control is a mechanism for temporarily stopping the transmission of data on Ethernet family computer networks. The goal of this mechanism is to ensure zero packet loss in the presence of network congestion.
The first flow control mechanism, the pause frame, was defined by the IEEE 802.3x standard.
A sending station (computer or network switch) may be transmitting data faster than the other end of the link can accept it. Using flow control, the receiving station can signal the sender requesting suspension of transmissions until the receiver catches up.
Use this command to disable the generation of Ethernet flow control (pause frames).
Example:
set interfaces pseudo-ethernet peth0 disable-flow-control
Use this command to direct an interface to not detect any physical state changes on a link, for example, when the cable is unplugged.
Default is to detects physical link state changes.
Example:
set interfaces pseudo-ethernet peth0 disable-link-detect
Configure user defined MAC address on given <interface>.
Example:
set interfaces pseudo-ethernet peth0 mac '00:01:02:03:04:05'
Configure MTU on given <interface>. It is the size (in bytes) of the largest ethernet frame sent on this link.
Example:
set interfaces pseudo-ethernet peth0 mtu 9000
Once a neighbor has been found, the entry is considered to be valid for at least for this specifc time. An entry’s validity will be extended if it receives positive feedback from higher level protocols.
This defaults to 30 seconds.
Example:
set interfaces pseudo-ethernet peth0 ip arp-cache-timeout 180
If set the kernel can respond to arp requests with addresses from other interfaces. This may seem wrong but it usually makes sense, because it increases the chance of successful communication. IP addresses are owned by the complete host on Linux, not by particular interfaces. Only for more complex setups like load-balancing, does this behaviour cause problems.
If not set (default) allows you to have multiple network interfaces on the same subnet, and have the ARPs for each interface be answered based on whether or not the kernel would route a packet from the ARP’d IP out that interface (therefore you must use source based routing for this to work).
In other words it allows control of which cards (usually 1) will respond to an arp request.
Example:
set interfaces pseudo-ethernet peth0 ip disable-arp-filter
Configure interface-specific Host/Router behaviour. If set, the interface will switch to host mode and IPv6 forwarding will be disabled on this interface.
set interfaces pseudo-ethernet peth0 ip disable-forwarding
Define behavior for gratuitous ARP frames who’s IP is not already present in the ARP table. If configured create new entries in the ARP table.
Both replies and requests type gratuitous arp will trigger the ARP table to be updated, if this setting is on.
If the ARP table already contains the IP address of the gratuitous arp frame, the arp table will be updated regardless if this setting is on or off.
set interfaces pseudo-ethernet peth0 ip enable-arp-accept
Define different restriction levels for announcing the local source IP address from IP packets in ARP requests sent on interface.
Use any local address, configured on any interface if this is not set.
If configured, try to avoid local addresses that are not in the target’s subnet for this interface. This mode is useful when target hosts reachable via this interface require the source IP address in ARP requests to be part of their logical network configured on the receiving interface. When we generate the request we will check all our subnets that include the target IP and will preserve the source address if it is from such subnet. If there is no such subnet we select source address according to the rules for level 2.
set interfaces pseudo-ethernet peth0 ip enable-arp-announce
Define different modes for sending replies in response to received ARP requests that resolve local target IP addresses:
If configured, reply only if the target IP address is local address configured on the incoming interface.
If this option is unset (default), reply for any local target IP address, configured on any interface.
set interfaces pseudo-ethernet peth0 ip enable-arp-ignore
Use this command to enable proxy Address Resolution Protocol (ARP) on this interface. Proxy ARP allows an Ethernet interface to respond with its own MAC address to ARP requests for destination IP addresses on subnets attached to other interfaces on the system. Subsequent packets sent to those destination IP addresses are forwarded appropriately by the system.
Example:
set interfaces pseudo-ethernet peth0 ip enable-proxy-arp
Private VLAN proxy arp. Basically allow proxy arp replies back to the same interface (from which the ARP request/solicitation was received).
This is done to support (ethernet) switch features, like RFC 3069, where the individual ports are NOT allowed to communicate with each other, but they are allowed to talk to the upstream router. As described in RFC 3069, it is possible to allow these hosts to communicate through the upstream router by proxy_arp’ing.
Note
Don’t need to be used together with proxy_arp.
This technology is known by different names:
In RFC 3069 it is called VLAN Aggregation
Cisco and Allied Telesyn call it Private VLAN
Hewlett-Packard call it Source-Port filtering or port-isolation
Ericsson call it MAC-Forced Forwarding (RFC Draft)
Enable policy for source validation by reversed path, as specified in RFC 3704. Current recommended practice in RFC 3704 is to enable strict mode to prevent IP spoofing from DDos attacks. If using asymmetric routing or other complicated routing, then loose mode is recommended.
strict: Each incoming packet is tested against the FIB and if the interface is not the best reverse path the packet check will fail. By default failed packets are discarded.
loose: Each incoming packet’s source address is also tested against the FIB and if the source address is not reachable via any interface the packet check will fail.
disable: No source validation
SLAAC RFC 4862. IPv6 hosts can configure themselves automatically when connected to an IPv6 network using the Neighbor Discovery Protocol via ICMPv6 router discovery messages. When first connected to a network, a host sends a link-local router solicitation multicast request for its configuration parameters; routers respond to such a request with a router advertisement packet that contains Internet Layer configuration parameters.
Note
This method automatically disables IPv6 traffic forwarding on the interface in question.
Example:
set interfaces pseudo-ethernet peth0 ipv6 address autoconf
EUI-64 as specified in RFC 4291 allows a host to assign iteslf a unique 64-Bit IPv6 address.
Example:
set interfaces pseudo-ethernet peth0 ipv6 address eui64 2001:db8:beef::/64
Do not assign a link-local IPv6 address to this interface.
Example:
set interfaces pseudo-ethernet peth0 ipv6 address no-default-link-local
Configure interface-specific Host/Router behaviour. If set, the interface will switch to host mode and IPv6 forwarding will be disabled on this interface.
Example:
set interfaces pseudo-ethernet peth0 ipv6 disable-forwarding
Place interface in given VRF instance.
See also
There is an entire chapter about how to configure a VRF, please check this for additional information.
Example:
set interfaces pseudo-ethernet peth0 vrf red
DHCP(v6)
RFC 2131 states: The client MAY choose to explicitly provide the identifier through the ‘client identifier’ option. If the client supplies a ‘client identifier’, the client MUST use the same ‘client identifier’ in all subsequent messages, and the server MUST use that identifier to identify the client.
Example:
set interfaces pseudo-ethernet peth0 dhcp-options client-id 'foo-bar'
Instead of sending the real system hostname to the DHCP server, overwrite the host-name with this given-value.
Example:
set interfaces pseudo-ethernet peth0 dhcp-options host-name 'VyOS'
The vendor-class-id option can be used to request a specific class of vendor options from the server.
Example:
set interfaces pseudo-ethernet peth0 dhcp-options vendor-class-id 'VyOS'
Only request an address from the DHCP server but do not request a default gateway.
Example:
set interfaces pseudo-ethernet peth0 dhcp-options no-default-route
The DHCP unique identifier (DUID) is used by a client to get an IP address from a DHCPv6 server. It has a 2-byte DUID type field, and a variable-length identifier field up to 128 bytes. Its actual length depends on its type. The server compares the DUID with its database and delivers configuration data (address, lease times, DNS servers, etc.) to the client.
set interfaces pseudo-ethernet peth0 duid '0e:00:00:01:00:01:27:71:db:f0:00:50:56:bf:c5:6d'
This statement specifies dhcp6c to only exchange informational configuration parameters with servers. A list of DNS server addresses is an example of such parameters. This statement is useful when the client does not need stateful configuration parameters such as IPv6 addresses or prefixes.
set interfaces pseudo-ethernet peth0 dhcpv6-options parameters-only
When rapid-commit is specified, dhcp6c will include a rapid-commit option in solicit messages and wait for an immediate reply instead of advertisements.
set interfaces pseudo-ethernet peth0 dhcpv6-options rapid-commit
Request only a temporary address and not form an IA_NA (Identity Association for Non-temporary Addresses) partnership.
set interfaces pseudo-ethernet peth0 dhcpv6-options temporary
DHCPv6 Prefix Delegation (PD)
VyOS 1.3 (equuleus) supports DHCPv6-PD (RFC 3633). DHCPv6 Prefix Delegation is supported by most ISPs who provide native IPv6 for consumers on fixed networks.
Some ISPs by default only delegate a /64 prefix. To request for a specific prefix size use this option to request for a bigger delegation for this pd <id>. This value is in the range from 32 - 64 so you could request up to a /32 prefix (if your ISP allows this) down to a /64 delegation.
The default value corresponds to 64.
To request a /56 prefix from your ISP use:
set interfaces pseudo-ethernet peth0 dhcpv6-options pd 0 length 56
Specify the interface address used locally on the interfcae where the prefix has been delegated to. ID must be a decimal integer.
It will be combined with the delegated prefix and the sla-id to form a complete interface address. The default is to use the EUI-64 address of the interface.
Example: Delegate a /64 prefix to interface eth8 which will use a local
address on this router of <prefix>::ffff, as the address 65534 will
correspond to ffff in hexadecimal notation.
set interfaces pseudo-ethernet peth0 dhcpv6-options pd 0 interface eth8 address 65534
Specify the identifier value of the site-level aggregator (SLA) on the interface. ID must be a decimal number greater then 0 which fits in the length of SLA IDs (see below).
Example: If ID is 1 and the client is delegated an IPv6 prefix 2001:db8:ffff::/48, dhcp6c will combine the two values into a single IPv6 prefix, 2001:db8:ffff:1::/64, and will configure the prefix on the specified interface.
set interfaces pseudo-ethernet peth0 dhcpv6-options pd 0 interface eth8 sla-id 1
Pseudo Ethernet/MACVLAN options
VLAN
IEEE 802.1q, often referred to as Dot1q, is the networking standard that supports virtual LANs (VLANs) on an IEEE 802.3 Ethernet network. The standard defines a system of VLAN tagging for Ethernet frames and the accompanying procedures to be used by bridges and switches in handling such frames. The standard also contains provisions for a quality-of-service prioritization scheme commonly known as IEEE 802.1p and defines the Generic Attribute Registration Protocol.
Portions of the network which are VLAN-aware (i.e., IEEE 802.1q conformant) can include VLAN tags. When a frame enters the VLAN-aware portion of the network, a tag is added to represent the VLAN membership. Each frame must be distinguishable as being within exactly one VLAN. A frame in the VLAN-aware portion of the network that does not contain a VLAN tag is assumed to be flowing on the native VLAN.
The standard was developed by IEEE 802.1, a working group of the IEEE 802 standards committee, and continues to be actively revised. One of the notable revisions is 802.1Q-2014 which incorporated IEEE 802.1aq (Shortest Path Bridging) and much of the IEEE 802.1d standard.
802.1q VLAN interfaces are represented as virtual sub-interfaces in VyOS. The
term used for this is vif.
Create a new VLAN interface on interface <interface> using the VLAN number provided via <vlan-id>.
You can create multiple VLAN interfaces on a physical interface. The VLAN ID range is from 0 to 4094.
Note
Only 802.1Q-tagged packets are accepted on Ethernet vifs.
Configure interface <interface> with one or more interface addresses.
address can be specified multiple times as IPv4 and/or IPv6 address, e.g. 192.0.2.1/24 and/or 2001:db8::1/64
dhcp interface address is received by DHCP from a DHCP server on this segment.
dhcpv6 interface address is received by DHCPv6 from a DHCPv6 server on this segment.
Example:
set interfaces pseudo-ethernet peth0 vif 10 address 192.0.2.1/24
set interfaces pseudo-ethernet peth0 vif 10 address 2001:db8::1/64
set interfaces pseudo-ethernet peth0 vif 10 address dhcp
set interfaces pseudo-ethernet peth0 vif 10 address dhcpv6
Set a human readable, descriptive alias for this connection. Alias is used by
e.g. the show interfaces command or SNMP based monitoring tools.
Example:
set interfaces pseudo-ethernet peth0 vif 10 description 'This is an awesome interface running on VyOS'
Disable given <interface>. It will be placed in administratively down
(A/D) state.
Example:
set interfaces pseudo-ethernet peth0 vif 10 disable
Use this command to direct an interface to not detect any physical state changes on a link, for example, when the cable is unplugged.
Default is to detects physical link state changes.
Example:
set interfaces pseudo-ethernet peth0 vif 10 disable-link-detect
Configure user defined MAC address on given <interface>.
Example:
set interfaces pseudo-ethernet peth0 vif 10 mac '00:01:02:03:04:05'
Configure MTU on given <interface>. It is the size (in bytes) of the largest ethernet frame sent on this link.
Example:
set interfaces pseudo-ethernet peth0 vif 10 mtu 9000
Once a neighbor has been found, the entry is considered to be valid for at least for this specifc time. An entry’s validity will be extended if it receives positive feedback from higher level protocols.
This defaults to 30 seconds.
Example:
set interfaces pseudo-ethernet peth0 vif 10 ip arp-cache-timeout 180
If set the kernel can respond to arp requests with addresses from other interfaces. This may seem wrong but it usually makes sense, because it increases the chance of successful communication. IP addresses are owned by the complete host on Linux, not by particular interfaces. Only for more complex setups like load-balancing, does this behaviour cause problems.
If not set (default) allows you to have multiple network interfaces on the same subnet, and have the ARPs for each interface be answered based on whether or not the kernel would route a packet from the ARP’d IP out that interface (therefore you must use source based routing for this to work).
In other words it allows control of which cards (usually 1) will respond to an arp request.
Example:
set interfaces pseudo-ethernet peth0 vif 10 ip disable-arp-filter
Configure interface-specific Host/Router behaviour. If set, the interface will switch to host mode and IPv6 forwarding will be disabled on this interface.
set interfaces pseudo-ethernet peth0 vif 10 ip disable-forwarding
Define behavior for gratuitous ARP frames who’s IP is not already present in the ARP table. If configured create new entries in the ARP table.
Both replies and requests type gratuitous arp will trigger the ARP table to be updated, if this setting is on.
If the ARP table already contains the IP address of the gratuitous arp frame, the arp table will be updated regardless if this setting is on or off.
set interfaces pseudo-ethernet peth0 vif 10 ip enable-arp-accept
Define different restriction levels for announcing the local source IP address from IP packets in ARP requests sent on interface.
Use any local address, configured on any interface if this is not set.
If configured, try to avoid local addresses that are not in the target’s subnet for this interface. This mode is useful when target hosts reachable via this interface require the source IP address in ARP requests to be part of their logical network configured on the receiving interface. When we generate the request we will check all our subnets that include the target IP and will preserve the source address if it is from such subnet. If there is no such subnet we select source address according to the rules for level 2.
set interfaces pseudo-ethernet peth0 vif 10 ip enable-arp-announce
Define different modes for sending replies in response to received ARP requests that resolve local target IP addresses:
If configured, reply only if the target IP address is local address configured on the incoming interface.
If this option is unset (default), reply for any local target IP address, configured on any interface.
set interfaces pseudo-ethernet peth0 vif 10 ip enable-arp-ignore
Use this command to enable proxy Address Resolution Protocol (ARP) on this interface. Proxy ARP allows an Ethernet interface to respond with its own MAC address to ARP requests for destination IP addresses on subnets attached to other interfaces on the system. Subsequent packets sent to those destination IP addresses are forwarded appropriately by the system.
Example:
set interfaces pseudo-ethernet peth0 vif 10 ip enable-proxy-arp
Private VLAN proxy arp. Basically allow proxy arp replies back to the same interface (from which the ARP request/solicitation was received).
This is done to support (ethernet) switch features, like RFC 3069, where the individual ports are NOT allowed to communicate with each other, but they are allowed to talk to the upstream router. As described in RFC 3069, it is possible to allow these hosts to communicate through the upstream router by proxy_arp’ing.
Note
Don’t need to be used together with proxy_arp.
This technology is known by different names:
In RFC 3069 it is called VLAN Aggregation
Cisco and Allied Telesyn call it Private VLAN
Hewlett-Packard call it Source-Port filtering or port-isolation
Ericsson call it MAC-Forced Forwarding (RFC Draft)
Enable policy for source validation by reversed path, as specified in RFC 3704. Current recommended practice in RFC 3704 is to enable strict mode to prevent IP spoofing from DDos attacks. If using asymmetric routing or other complicated routing, then loose mode is recommended.
strict: Each incoming packet is tested against the FIB and if the interface is not the best reverse path the packet check will fail. By default failed packets are discarded.
loose: Each incoming packet’s source address is also tested against the FIB and if the source address is not reachable via any interface the packet check will fail.
disable: No source validation
SLAAC RFC 4862. IPv6 hosts can configure themselves automatically when connected to an IPv6 network using the Neighbor Discovery Protocol via ICMPv6 router discovery messages. When first connected to a network, a host sends a link-local router solicitation multicast request for its configuration parameters; routers respond to such a request with a router advertisement packet that contains Internet Layer configuration parameters.
Note
This method automatically disables IPv6 traffic forwarding on the interface in question.
Example:
set interfaces pseudo-ethernet peth0 vif 10 ipv6 address autoconf
EUI-64 as specified in RFC 4291 allows a host to assign iteslf a unique 64-Bit IPv6 address.
Example:
set interfaces pseudo-ethernet peth0 vif 10 ipv6 address eui64 2001:db8:beef::/64
Do not assign a link-local IPv6 address to this interface.
Example:
set interfaces pseudo-ethernet peth0 vif 10 ipv6 address no-default-link-local
Configure interface-specific Host/Router behaviour. If set, the interface will switch to host mode and IPv6 forwarding will be disabled on this interface.
Example:
set interfaces pseudo-ethernet peth0 vif 10 ipv6 disable-forwarding
Place interface in given VRF instance.
See also
There is an entire chapter about how to configure a VRF, please check this for additional information.
Example:
set interfaces pseudo-ethernet peth0 vif 10 vrf red
DHCP(v6)
RFC 2131 states: The client MAY choose to explicitly provide the identifier through the ‘client identifier’ option. If the client supplies a ‘client identifier’, the client MUST use the same ‘client identifier’ in all subsequent messages, and the server MUST use that identifier to identify the client.
Example:
set interfaces pseudo-ethernet peth0 vif 10 dhcp-options client-id 'foo-bar'
Instead of sending the real system hostname to the DHCP server, overwrite the host-name with this given-value.
Example:
set interfaces pseudo-ethernet peth0 vif 10 dhcp-options host-name 'VyOS'
The vendor-class-id option can be used to request a specific class of vendor options from the server.
Example:
set interfaces pseudo-ethernet peth0 vif 10 dhcp-options vendor-class-id 'VyOS'
Only request an address from the DHCP server but do not request a default gateway.
Example:
set interfaces pseudo-ethernet peth0 vif 10 dhcp-options no-default-route
The DHCP unique identifier (DUID) is used by a client to get an IP address from a DHCPv6 server. It has a 2-byte DUID type field, and a variable-length identifier field up to 128 bytes. Its actual length depends on its type. The server compares the DUID with its database and delivers configuration data (address, lease times, DNS servers, etc.) to the client.
set interfaces pseudo-ethernet peth0 vif 10 duid '0e:00:00:01:00:01:27:71:db:f0:00:50:56:bf:c5:6d'
This statement specifies dhcp6c to only exchange informational configuration parameters with servers. A list of DNS server addresses is an example of such parameters. This statement is useful when the client does not need stateful configuration parameters such as IPv6 addresses or prefixes.
set interfaces pseudo-ethernet peth0 vif 10 dhcpv6-options parameters-only
When rapid-commit is specified, dhcp6c will include a rapid-commit option in solicit messages and wait for an immediate reply instead of advertisements.
set interfaces pseudo-ethernet peth0 vif 10 dhcpv6-options rapid-commit
Request only a temporary address and not form an IA_NA (Identity Association for Non-temporary Addresses) partnership.
set interfaces pseudo-ethernet peth0 vif 10 dhcpv6-options temporary
DHCPv6 Prefix Delegation (PD)
VyOS 1.3 (equuleus) supports DHCPv6-PD (RFC 3633). DHCPv6 Prefix Delegation is supported by most ISPs who provide native IPv6 for consumers on fixed networks.
Some ISPs by default only delegate a /64 prefix. To request for a specific prefix size use this option to request for a bigger delegation for this pd <id>. This value is in the range from 32 - 64 so you could request up to a /32 prefix (if your ISP allows this) down to a /64 delegation.
The default value corresponds to 64.
To request a /56 prefix from your ISP use:
set interfaces pseudo-ethernet peth0 vif 10 dhcpv6-options pd 0 length 56
Specify the interface address used locally on the interfcae where the prefix has been delegated to. ID must be a decimal integer.
It will be combined with the delegated prefix and the sla-id to form a complete interface address. The default is to use the EUI-64 address of the interface.
Example: Delegate a /64 prefix to interface eth8 which will use a local
address on this router of <prefix>::ffff, as the address 65534 will
correspond to ffff in hexadecimal notation.
set interfaces pseudo-ethernet peth0 vif 10 dhcpv6-options pd 0 interface eth8 address 65534
Specify the identifier value of the site-level aggregator (SLA) on the interface. ID must be a decimal number greater then 0 which fits in the length of SLA IDs (see below).
Example: If ID is 1 and the client is delegated an IPv6 prefix 2001:db8:ffff::/48, dhcp6c will combine the two values into a single IPv6 prefix, 2001:db8:ffff:1::/64, and will configure the prefix on the specified interface.
set interfaces pseudo-ethernet peth0 vif 10 dhcpv6-options pd 0 interface eth8 sla-id 1