161 lines
4.9 KiB
Markdown
161 lines
4.9 KiB
Markdown
interfaces-tunnel(5)
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# NAME
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*interfaces-tunnel* - Tunnel extensions for the interfaces(5) file format
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# DESCRIPTION
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The following options set up tunneling interfaces with ifupdown-ng.
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# TUNNEL-RELATED OPTIONS
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A tunnel interface must have a mode, remote IP and a local IP or device
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set, all other options are optional.
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*tunnel-mode* _mode_
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Denotes the mode for this tunnel. Basically all tunnel modes supported
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by Linux / iproute2 are supported as well. This includes but is not
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limited to _gre_/_gretap_, _ip6gre_/_ip6gretap_, _ipip_/_ip6ip_/_sit_.
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*tunnel-local* _IP_
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Denotes the IP address used as the local tunnel endpoint. According
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to the _tunnel-mode_ an IPv4 or IPv6 address has to be given.
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For compatiblity to ifupdown1 _local_ is an alias for this option.
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*tunnel-local-dev* _interface_
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When the local IP address the tunnel should be established from isn't
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static and therefore might change (e.g. configured by DHCP or PPP) it
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might be desireable to just use the address configured on _interface_.
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When _tunnel-local-dev_ is given instead of _tunnel-local_ ifupdown-ng
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will try to determine the IP address set on the given _interface_ with
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respect to the address family required to set up a tunnel of the given
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_mode_ and use this to set up the tunnel.
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*tunnel-remote* _IP_
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Denotes the IP address used as the remote tunnel endpoint. According
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to the _tunnel-mode_ an IPv4 or IPv6 address has to be given.
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For compatiblity to ifupdown1 _endpoint_ is an alias for this option.
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*tunnel-physdev* _interface_
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Denotes the _interface_ the encapsulated packets should be sent out by.
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This comes in handy when using VRFs to denote that the local tunnel
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endpoint should be terminated in VRF _interface_ or the VRF associated
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with _interface_.
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Note: Depending on the _mode_ of the tunnel either the VRF interface
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or the real underlay interface may have to given as _interface_.
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*tunnel-ttl* _ttl_
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Denotes the TTL value to use in outgoing packets. _ttl_ is a number in the
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range 1 - 255 whereas 0 is a special value meaning that packets inherit the
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TTL value. The default for IPv4 tunnels is to inherit the TTL, for IPv6
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tunnels it's 64. For compatiblity to ifupdown1 _ttl_ is an alias for this option.
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# IPIP/SIT-RELATED OPTIONS
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*tunnel-encap* _encap_
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Denotes the type of secondary UDP encapsulation to use for this tunnel
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if any. Supported _encap_ values are _fou_, _gue_, and _none_.
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_fou_ indicates Foo-Over-UDP, _gue_ indicates Generic UDP Encapsulation.
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# GRE-RELATED OPTIONS
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*tunnel-encap* _encap_
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Denotes the type of secondary UDP encapsulation to use for this tunnel
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if any. Supported _encap_ values are _fou_, _gue_, and _none_.
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_fou_ indicates Foo-Over-UDP, _gue_ indicates Generic UDP Encapsulation.
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*tunnel-key* _key_
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Denotes the_key to used for keyed GRE to allow multiple tunnels between
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the same two endpoints. _key_ is either a number or an IPv4 address-
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like dotted quad. The key parameter specifies the same key to use in both
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directions. The _tunnel-ikey_ and _tunnel-okey_ parameters specify different
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keys for input and output. For compatiblity to ifupdown1 _key_ is an alias
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for this option.
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*tunnel-hoplimit* _ttl_
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Denotes the Hop Limit value to use in outgoing packets for _ip6gre_/_ip6gretap_
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tunnels.
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*tunnel-ignore-df* _bool_
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Denotes wether to enable/disable IPv4 DF suppression on this tunnel. Normally
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datagrams that exceed the MTU will be fragmented; the presence of the DF flag
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inhibits this, resulting instead in an ICMP Unreachable (Fragmentation Required)
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message. Enabling this attribute causes the DF flag to be ignored.
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*tunnel-ikey* _key_
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Denotes the key to used for keyed GRE for packets received. See _tunnel-key_
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for details.
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*tunnel-okey* _key_
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Denotes the key to used for keyed GRE for packets sent out. See _tunnel-key_
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for details.
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*tunnel-pmtudisc* _bool_
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Denotes wether to enable/disable Path MTU Discovery on this tunnel. It is
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enabled by default. Note that a fixed ttl is incompatible with this option:
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tunneling with a fixed ttl always makes pmtu discovery.
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*tunnel-tos* _tos_
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Denotes the TOS value to use in outgoing packets.
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# EXAMPLES
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A simple GRE tunnel
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```
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auto gre0
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iface gre0
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tunnel-mode gre
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tunnel-remote 198.51.100.1
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tunnel-local 203.0.113.2
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#
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address 192.0.2.42/24
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address 2001:db8::42/64
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```
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A GRE tunnel where the local IP is learned from _eth0_
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```
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auto gre1
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iface gre1
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tunnel-mode gre
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tunnel-remote 198.51.100.1
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tunnel-local-dev eth0
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#
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address 192.0.2.42/24
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address 2001:db8::42/64
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```
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A GRE tunnel which transfers encapasulated packets via _eth0_ which is part
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of a VRF.
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```
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auto eth0
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iface eth0
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address 203.0.113.2/24
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gateway 203.0.113.1
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vrf vrf_external
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auto tun-vrf
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iface tun-vrf
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tunnel-mode gre
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tunnel-remote 198.51.100.1
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tunnel-local 203.0.113.2
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tunnel-physdev eth0
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#
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address 192.0.2.42/24
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address 2001:db8::42/64
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auto vrf_external
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iface vrf_external
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vrf-table 1023
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```
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# AUTHORS
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Maximilian Wilhelm <max@sdn.clinic>
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