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Questions tagged [gre]

Generic Routing Encapsulation (GRE) is a tunneling protocol, developed by Cisco.

Generic Routing Encapsulation (GRE) is a tunneling protocol, developed by Cisco.

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GRE protocol type for Ethernet over GRE?

For a IP over GRE tunnel, as defined by the RFC 2784, the "protocol" field is filled with 0x0800 (defined as ETH_P_IP in the Linux kernel according to this source http://www.scs.stanford.edu/histar/src/uinc/linux/if_ether.h) I have looked online,…
dreadiscool
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Iptables not routing GRE protocol

First things first, there might be a few English errors, considering it's not my native language. I'm having a problem with VPN(GRE protocol) passing through Iptables. I've done this at least a dozen times, but this time it's simply not working. I…
Carlos Parisotto
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https connection can't established behind a gre tunnel

I have a network topological graph like this: Local box GateWay box +---------------+ +--------------------------+ |192.168.1.200 | -> |192.168.1.2 10.2.10.2 | +---------------+ +--------------------------+ …
armnotstrong
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Set up transparent GRE/VPN to redirect all traffic to an External datacenter

I need to setup an existing server with multiple IPs (from OVH) to send all the traffic (through VPN or GRE tunnel) to an external server that has only 1 Public IP. I want to make it like every local IP in the external datacenter has a OVH IP on the…
CappyT
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How to route outbound traffic for a particular destination IP address to GRE Tunnel in CentOS?

Hello I am trying to configure a network like this network diagram :- Well I have to create a GRE Tunnel at my alpha server and route some particular traffic to GRE Tunnel.I want to do the configs on CentOS.I will explain the scenario below :- I…
Rishabh Agnihotri
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GRE Tunnel Collapsing in One Direction

This is a related question to another thread I posted. I'm having an issue where my GRE tunnel is collapsing in one direction, but can be reopened by ping the other server using the GRE Interface. I'm aware that Cisco routers using keepalive packets…
Brian McDonald
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Public IP not responding because routing table...?

Fixed with: /etc/iproute2/rt_tables 1 tble_eth0 /etc/sysconfig/network-scripts/route-eth0 104.000.64.0/18 dev eth0 src 104.000.65.38 table tble_eth0 default via 104.000.64.1 dev eth0 src 104.000.65.38 table…
OnTheFly
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TLS-intolerant sites suddenly not working

About 2 weeks ago users started reporting that they were unable to access two https-only sites. When I inspected these sites I found they were completely intolerant to TLS. In order to connect, SSL3 was required and TLS (1.0-1.2) must be disabled in…
user252280
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Listening "through" GRE Tunnel

Currently I'm looking to learn about using GRE Tunnels and I have the following scheme: Server1 (200.1.2.3) ----> Server2 (190.1.2.3) Both servers have public IPs Then I've setup a GRE Tunnel with the following commands I've found on internet On…
Rodrigo
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How is my GRE-Tunneled packet being routed?

I'm trying to figure out exactly what is happening when I create a GRE tunnel. My network looks like this (-> means directly connected): Computer A (eth0: 10.0.1.1) -> (eth0: 10.0.1.2) Router B (eth1: 10.0.2.1) -> (eth0: 10.0.2.2) Router C…
exxodus7
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IP/GRE compiled in kernel but gre0 interface doesnt exist

Im trying to create IP over GRE tunnel but i get No such device: ip tunnel add gre0 mode gre remote 192.168.152.22 local 192.168.152.21 ttl 255 ioctl: No such device I have compiled GRE support in my…
MABC
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DMVPN and OSPF (two tunnels dynamic routing)

please help me to resolve the problem with routing between dmvpn GRE tunnels. I've got a DMVPN HUB and SPOKE topology. HUB has public ip address in internet. SPOKE has two ISPs for redundancy. I've decided to create two GRE tunnels between HUB and…
HFFreeway
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Using public interfaces on a server connected through a GRE tunnel

I'm pretty new to networking so please forgive any terminology mistakes. I have 2 servers connected with a GRE tunnel. Server1 (10.0.0.1) ----> Server2 (10.0.0.2) I want to be able to bind to the public IPs on Server2 using Server1. To do this, I…
Evan
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GRE keepalive with Linux and RouterOS

I have a Linux host and couple of routerboadrs. I created a GRE tunnel, but Linux does not answer keepalive packages. Then router mark gre connection as unreachable, so I cant send to Linux host from router subnet. If linux sends something into…
eri
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GRE: read from PTY failed error when connecting multiple clients to PPTP

I have just installed a pptp server and now I can make it work. The problem is, it can only be connected to by one client. How do I set it up so that it will allow multiple users? Here is the error log that is thrown after the second user tries to…
reikyoushin
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