NAME
etherip —
EtherIP tunnel interface
SYNOPSIS
pseudo-device etherip
DESCRIPTION
The etherip driver provides point-to-point
tunnel interfaces for carrying Ethernet frames across IPv4 and IPv6 networks
using RFC 3378 EtherIP encapsulation.
An etherip interface can be created using
the ifconfig etheripN
create command or by setting up a
hostname.if(5) configuration file for
netstart(8). It must be configured with the addresses used for the
outer header. This can be done using
ifconfig(8)'s tunnel command (which uses the
SIOCSLIFPHYADDR ioctl). The
sysctl(2)
variable net.inet.etherip.allow must be set to 1,
unless ipsec(4) is being used to protect the traffic.
etherip interfaces can configured as part
of an Ethernet bridge, such as veb(4), tpmr(4), and
bridge(4),
to extend the connectivity of Ethernet networks across IP networks, possibly
across the Internet.
The EtherIP protocol does not provide any integrated security features. EtherIP should only be deployed on trusted private networks, or protected with IPsec to add authentication and encryption for confidentiality. IPsec is especially recommended when transporting EtherIP over the public Internet. EtherIP encapsulated packets may be protected with IPsec by specifying the appropriate IPsec flows between the two endpoints. To only protect the encapsulated EtherIP traffic between the tunnel endpoints, the IP transport protocol 97 (etherip) selector may be used in ipsec.conf(5) or iked.conf(5).
EXAMPLES
Given two physically separate Ethernet networks,
etherip can be used as follows to make them appear
as the same local area network. If host gw1 has the external IP address
192.0.2.10 and is connected to network1 on em1, and host gw2 has the
external IP address 198.51.100.14 and is connected to network2 on ix1, the
following configuration can be used to bridge network1 and network2.
First create a bridge using a
veb(4)
interface, adding the etherip interface and internal
Ethernet interface to the bridge.
On gw1:
gw1# ifconfig etherip0 create tunnel 192.0.2.10 198.51.100.14 gw1# ifconfig veb0 create add etherip0 add em1
On gw2:
gw2# ifconfig etherip0 create tunnel 198.51.100.14 192.0.2.10 gw2# ifconfig veb0 create add etherip0 add ix1
Create Security Associations (SAs) between the external IP address of each bridge and matching ingress flows by using the following ipsec.conf(5) file on gw1:
esp from 198.51.100.14 to 192.0.2.10 spi 0x4242:0x4243 \
authkey file "auth1:auth2" enckey file "enc1:enc2"
flow esp proto etherip from 198.51.100.14 to 192.0.2.10
Now load these rules into the kernel by issuing the ipsecctl(8) command:
gw1# ipsecctl -f ipsec.conf
Appropriate ipsec.conf(5) for gw2:
esp from 198.51.100.14 to 192.0.2.10 spi 0x4243:0x4242 \
authkey file "auth2:auth1" enckey file "enc2:enc1"
flow esp proto etherip from 198.51.100.14 to 192.0.2.10
And load them:
gw2# ipsecctl -f ipsec.conf
Finally, bring all the interfaces up (if not already up).
On gw1:
gw1# ifconfig em1 up gw1# ifconfig etherip0 up gw1# ifconfig veb0 up
On gw2:
gw1# ifconfig ix1 up gw1# ifconfig etherip0 up gw1# ifconfig veb0 up
SEE ALSO
sysctl(2), bridge(4), inet(4), inet6(4), ipsec(4), tpmr(4), veb(4), hostname.if(5), iked.conf(5), ipsec.conf(5), ifconfig(8), netstart(8)
STANDARDS
R. Housley and S. Hollenbeck, EtherIP: Tunneling Ethernet Frames in IP Datagrams, RFC 3378, September 2002.
HISTORY
The etherip device first appeared in
OpenBSD 5.9.
AUTHORS
The etherip driver was written by
Kazuya Goda
<goda@openbsd.org>.