Questions tagged [gre]

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

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Connection Refused (GRE Tunnel - FiveM)

I am running a game server using Vultr. What I am trying to do is run the game server (backend server) through a GRE Tunnel. For this, I am using x4b.net for my GRE Tunnel. A few things to note: The ...
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GRETAP over IPSEC ESP using ip-xfrm

I need to set up an IPSEC tunnel between two systems using ip xfrm commands, suitable for running ISIS over. Thanks to examples on the web, I am able to create either an XFRM or VTI link that works ...
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Force UDP traffic to exit through the GRE Tunnel

I have an application that suffers from ddos. So we put it behind a filter that works on the basis of GRE. The filter works fine, but the application has a subapplication that answers to other ports ...
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GRE tunnel. Port Forwarding with IPTables from VPS to Local Server not working

Dear ServerFault community, I have an OVH VPS with 3 public IPs (1.1.1.1, 2.2.2.2, 3.3.3.3) and I am trying to forward them individually, with one tunnel for each IP, to a server in my office (IP 5.5....
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GRE set outbound IP route

Node A Public IP: 198.244.xxx.151 Node B Public IP: 37.59.xxx.234 Node A: sudo ip tunnel add gre1 mode gre local 198.244.xxx.151 remote 37.59.xxx.234 ttl 255 sudo ip addr add 10.0.0.1/30 dev gre1 sudo ...
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Attempting to GRE tunnel IP block through public IP (OVH > Hetzner)

I am attempting to route an IPv4 /28 block through my OVH server to a server I have with Hetzner through their main public IPs. I found a guide attached below but I am unable to ping 164.132.xxx.1 ...
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Using OVH VPS as a shield to dedicated machine

I am having a few dedicated machines in a few hosting companies which either do not offer DDOS protection or their protection is awful. I've been contacting a few hosting companies and friends and got ...
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Reach private subnets on secondary interfaces between GRE tunnel endpoints

I have two servers in different locations. Each server has an eth0 with a public IP (internet accessible) and an eth1 with a private IP connected to the internal network. Server A eth0: 1.2.3.4 (...
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How can I setup and verify GRE tunnel pn ubuntu server?

In the scenario below, I'm going to configure SQUID and WCCP for web caching mechanism. Currently, WCCP is configured on router and squid is configured on UbuntuServer, but really I do not know ...
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does google cloud support ipsec encapsulated gre tunnels

I can't seem to get a pim set up on google cloud where multicast traffic is sent over a ipsec encapsulated gre tunnel. Does google cloud ec2 instances and network block this type of traffic?
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Cisco GRE routing semantics to ip_gre

I am reading this article about setting up a GRE IP Tunnel: https://packetpushers.net/anatomy-of-gre-tunnels/ There's a section about creating a GRE tunnel interface on router A R1: interface ...
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Connecting to server via VPN

There is a server with connection via VPN to it (using GRE protocol). I have got a problem to connect to this VPN from home network, because GRE is not allowed by provider. But I have got another work ...
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Subscribe to a multicast broadcast after connecting to GRE tunnel

I created a gre tunnel to a ip that's doing multicast broadcasting. I look at tcpdump and I see that there are two messages that keep repeating PIMv2 98 bytes long Info Hello IGMPv2 72 bytes long Info ...
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setting up gre tunnel on debian with tunnel source and tunnel destination

I am trying to setup a gre tunnel on debian to receive broadcast packets. I have the information for an interface ip address [10.16.2.4 255.255.255.192] tunnel source [10.16.0.2] tunnel destination [...
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IP Binding Issue in using GRE Tunnel

I have a issue with tunneling and am having a hard time finding a solution. I have two servers, A: Host-Server being a sever with a single IP, and B: Main-Server being the server handling all our ...
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Routing one machine's traffic through GRE tunnel to a remote NAT

I had to solve the following dilemma for a friend and thought I'd document how we did it here... Here's the situation: His home network 192.168.1.0/24 and it sits behind a Linux router that performs ...
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GRE tunneling using Open vSwitch

I am trying to implement tunneling as described here with the following setup (without any success): ho1 is a host only interface. I want to connect Nested Guest 11 and Nested Guest 21. I have read ...
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Use working GRE tunnel as default on remote server

Purpose is to "protect" my backend dedicated server (B) using a front VPS (A) with a GRE tunnel and use the the new stablished interface (GRE1) as default on (B) in order not to leak the ...
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PPTP & GRE issue iptables/NAT

This is my first post and will try my best to add all the info. I am trying to accomplish something that i am not sure if it is supported, basically I have a firewall that is configure to allow ...
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How can I set up a point-to-point IPv6 GRE tunnel encrypted with ipsec between my Mikrotik CCR2004 router and a Linux host running Strongswan?

I need to encapsulate IPv4 in IPv6 for routing purposes. One end is a Linux box running quagga, and the other end is a Mikrotik CCR2004. How?
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EdgeRouter Route Incoming Traffic to another Public Network/Server

I am curious if this is possible in theory? At my colo datacenter, I have a lot of public IP addresses (/21) on a 1GB circuit using an Edge Router 6P (not using BGP). I want to temporarily rent a ...
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Unable to setup a GRE tunnel between 2 servers

I currently have 2 servers: Server A: 2.2.2.2 Server B: 3.3.3.3 I want to create a GRE tunnel from server A to server B. I have ipforwarding enabled on server A: cat /proc/sys/net/ipv4/ip_forward 1 ...
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A gre tunnel between Mikrotik and Cisco router

I really need your help I'm trying to connect a Mikrotik router with a Cisco router with GRE tunnel using Public IPS the problem is when I try to configure keep alive between both routers the tunnel ...
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Reading back Linux gre[tap] local/remote address

With iproute2 on Linux, gre/gretap interfaces are setup with ip link add, which for GRE needs remote and optionally local attributes specifying the endpoints. However, I can't find any way to read ...
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Setting up a GRE tunnel on Windows Server 2019

I am trying to etablish an GRE tunnel to my Windows Server 2019, which seems easy enough. Although things get a bit complicated, as I want my applications to bind to the IP on the other side of the ...
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preventing ipv6 packets from being generated when creating a gre tunnel

I have a veth device, each side of it is in a different network namespace on the same machine. I am creating a gretap tunnel over this veth. when setting the gretap device to up state I can see a lot ...
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Suppressing ICMP protocol 47 unreachable with userspace GRE implementation

For reasons that would require a lot of irrelevant context to explain, I'm handling GRE packets with a userspace process with a SOCK_RAW/IPPROTO_GRE socket. This is working fine, except that despite ...
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Tunnel Linux traffic to Windows

I have two servers. Windows and Linux. Let's say Linux has the IP 1.2.3.4 and Windows 5.6.7.8. I want all traffic to be forwarded to windows as a tunnel. If I connect with 1.2.3.4:329 I want to ...
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Forwarding Home Game-Server through GRE Tunnel | Can't ping remote GRE IPs

I am having trouble routing my game-servers through GRE. I do not receive a ping from either side when pinging them. I can ping the local GRE interface; however, I cannot ping the remote GRE interface....
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Packets not getting forwarded on Centos7 between GRE tunnels

I'm have configured GRE tunnels between centos machines and corresponding routing tables on individual centos machines as shown in the image: I dont have enough reputation to post images Router1-----...
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Interface bonding on GRE tunnel with nmcli

I have two Ubuntu server-based routers and I'd like to bond (in broadcast mode, since I only care about redundancy) a radio link (where the radio equipment is connected to an Ethernet port) and a LTE ...
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gretap tunnel return traffic not being handled

I'm using iproute2 to add a GRE layer 2 tunnel with a vlan tag as shown below. ip link add name gre1 type gretap local 10.0.0.2 remote 8.8.8.8 ip link add name gre1.100 link gre1 type vlan proto 802....
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How to route server_A's internet traffic through server_B using a GRE Tunnel?

I have two Linux servers. I want to use a GRE tunnel to route all internet traffic from ClientBox through a tunnel to GatewayBox, so that, to the rest of the internet, my ClientBox appears to be ...
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ACK packet lost in GRE tunnel for IPv6 in IPv4

At home (79.1.1.156), my ISP doesn’t provide IPv6 so I’m connecting my server to an external server (95.1.1.126) that has IPv6 access via a GRE tunnel, with this simple setup: ip tunnel add gretun ...
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Seperate GRE tunnels cannot ping eachother

I have two systems that both tunnel to a core routing server. These systems both have a client address from the same /64 IPv6 prefix. From each client, I can ping the server with no problems and vice ...
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GRE Tunnel Dies in 1 direction

I have built a GRE tunnel over tap0 interface between 2 Centos-7 hosts. I've done this via the following: Host-A: 10.0.10.5 Host-B: 10.0.20.5 On host A: ip tunnel add tap0 mode gre remote 10.0.20....
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Route incoming traffic through GRE tunnel

So I have a VPS and Dedi server both running Debian 9.9. 139.99.x.x: VPS 139.89.x.x: DEDI The Dedi server runs a game server but can't be directly accessible, I want to route all traffic through my ...
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GRE traffic not forwarded to local subnet

I have two debian machines in difference locations and want to enable routing between the two internal subnets via GRE. My general routing is already working, meaning any internal machine directs ...
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Using iptables NAT to forward GRE tunnel

I have two hosts which need to have a GRE tunnel between them. In between the two I have a relay host which needs to perform NAT and forward the GRE traffic in either direction. grehostA --- ...
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Allow GRE (IP protocol 47) over Linux router NAT for a subnet

I have network setup as shown below: The VPN server running is windows 2012 server default VPN, which uses GRE protocol. I am able to have VPN connection to that remote vpn server, from my intranet ...
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ERSPAN to IP on Centos host with multi interfaces on the same subnet

I have an interesting configuration and would like some help getting it to work. On a hardware network monitoring probe, i have 2 physical interfaces. mgmt is the management interface and mon1 is a ...
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Linux GRE Tunnel: Remote Address parameter

The Linux GRE tunnel as two parameters, local address and remote address. Suppose I have two routers, the left one is outside of a NAT and right one is inside NAT, then I want to create a GRE tunnel ...
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GRE perfomance issue on Linux

I got a strange GRE perfomance issue. The setup is shown bellow. [host1] --- GRE over Eth 1G --- [linux router] --- Eth 10G --- [host2] Iperf transfer rate host1>host2 reaches 950Mbps. It encreases ...
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tc qdisc with GRE in openwrt

I'm trying to implement traffic control to GRE interface in an openwrt board. For this i followed below steps, Create GRE interface named gre1 in both tunnel end devices. Tested reachability with ...
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How to setup a GRE 3 host mesh without loops and forwards with OpenVSwitch?

I'm setting up a quite simple 3 host Proxmox (Debian) HA cluster. All VMs should be in the same subnet and when one fails over to another host inside the VM no reconfiguration should be required and ...
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Packet loss in IpSec/GRE tunnel

This is my setup: +--------------------+ +-------------------+ +--------------------+ | Router B a +-----+ Router+Firewall C | | b Router D | | 10.10.10.1 -----------...
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GRE Tunneling not working

i've been looking everywhere for a solution to this but have found really nothing. I was wondering if it is possible to forward ports such as 80 through an OpenVPN connection? I am using an OVH VPS ...
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Get IP over DHCP for GRE-tunnel

I need to create a GRE tunnel from a client to a server. This is my setup. Setup: ________________________________ _________________________________ ______________________________ |Server ...
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Bonding over OpenVPN, for fault tolerance

I have two OpenVPN server, and two machines connecting to them. Server 1 openvpn address: 10.158.1.1 Server 2 openvpn address: 10.158.2.1 Machine 1 has address 10.158.1.11 on server 1, 10.158.2.11 ...
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iptables SNAT not working for GRE packets

I am trying to apply SNAT to a PPTP client. The TCP/1723 packets are being SNATed properly but not the GRE ones. Can anyone spot what's wrong? I have the following iptables configuration: $ sudo ...
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