Introduction
Sub-menu: /interface gre
Standards: RFC1701
GRE (Generic Routing Encapsulation) is a tunneling protocol that was originally developed by Cisco GRE RFC 1701. It can encapsulate a wide variety of protocols creating a virtual point-to-point link.
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Properties
| Property | Description |
|---|---|
| allow-fast-path (yes | no; Default: yes) | Whether to allow FastPath processing. Must be disabled if IPsec tunneling is used. |
| clamp-tcp-mss (yes | no; Default: yes) | Controls whether to change MSS size for received TCP SYN packets. When enabled, a router will change the MSS size for received TCP SYN packets if the current MSS size exceeds the tunnel interface MTU (taking into account the TCP/IP overhead). The received encapsulated packet will still contain the original MSS, and only after decapsulation the MSS is changed. |
| comment (string; Default: ) | Short description of the tunnel. |
| disabled (yes | no; Default: no) | Enables/disables tunnel. |
| dont-fragment (inherit | no; Default: no) | Whether to include DF bit in related packets. |
| dscp (inherit | integer [0-63]; Default: ) | Set dscp value in Gre header to a fixed value or inherit from dscp value taken from tunnelled traffic |
| ipsec-secret (string; Default: ) | When secret is specified, router adds dynamic ipsec IPsec peer to remote-address with pre-shared key and policy with default values (by default phase2 uses sha1/aes128cbc). |
| keepalive (integer[/time],integer 0..4294967295; Default: 10s,10) | Tunnel keepalive parameter sets the time interval in which the tunnel running flag will remain even if the remote end of tunnel goes down. If configured time,retries fail, interface running flag is removed. Parameters are written in following format: KeepaliveInterval,KeepaliveRetries where KeepaliveInterval is time interval and KeepaliveRetries - number of retry attempts. By default keepalive is set to 10 seconds and 10 retries. |
| l2mtu (integer [0..65536]; Default: 65535) | Layer2 Maximum transmission unit. |
| local-address (IP; Default: 0.0.0.0) | IP address that will be used for local tunnel end. If set to 0.0.0.0 then IP address of outgoing interface will be used. |
| mtu (integer [0..65536]; Default: 1476) | Layer3 Maximum transmission unit. |
| name (string; Default: ) | Name of the tunnel. |
| remote-address (IP; Default: ) | IP address of remote tunnel end. |
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| Code Block | ||
|---|---|---|
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/ip address add address=172.16.1.1/30 interface=myGre /ip route add dst-address=10.1.202.0/24 gateway=172.16.1.2 |
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| Code Block | ||
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/ip address add address=172.16.1.2/30 interface=myGre /ip route add dst-address=10.1.101.0/24 gateway=172.16.1.1 |
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