Tagged Questions

Routing (in IP-based networks) is the process of selecting paths in a network along which to send network traffic.

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1answer
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Redirect Packets from ppp0 interface to ethernet interface in linux

My question is similar to this question, however with some change. I have a PPPoE connection on my Linux Machine (CentOS kernal 2.6.32) as a client, so that when I setup this connection, another ...
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3answers
2k views

How can I disable automatic IPv6 neighbor route advertisement on a router?

I work for an ISP that's in the process of making its infrastructure IPv6-ready. Our core routers already have a working setup, but a large portion of our fiber customers are behind a router running ...
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1answer
2k views

Change remote host IP address without losing control (Linux)

How can I change a remote host primary IP address without getting disconnected at all (without being in a "no IP addr" state). The matter is poorly discussed on Internet (according to my research). ...
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2answers
498 views

Why can I reach a different interface's IP address?

I'm wondering about this, and I can't seem to find an explanation on the internet. I have a linux gateway which has multiple interfaces: eth0: external ip eth1: 172.16.1.1/24 eth2: 172.16.2.1/24 ...
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1answer
947 views

Share Internet Connection from computer to new router

On my linux computer I have an external wlan adapter which is connected wirelessly to internet (an access point). Now I want to connect my linux computer via ethernet cable to a new ddwrt router. This ...
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1answer
238 views

PPTP server with NIC aliases

I have set up a VPN on a VPS Server using PPTP. I have one NIC with two aliases. eth0 eth0:1 eth0:2 The 3 interfaces have public addresses. eth0 is a French IP, eth0:1 is UK, and eth0:2 is ...
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4answers
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How to remove all default gateways

I'm running a custom built linux machine, so not all linux commands are available. I execute network related commands, so I need to set a default gateway right before I run my command, then remove ...
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2answers
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iptables --set-mark - Route diferent ports through different interfaces

Short story, 3 interfaces, eth0 (LAN), eth1(ADSL), eth2(4G). eth0 -> eth1: Works (ports 80, 443, 4070) eth0 -> eth2: Doesn't happen This is a graphical representation of the idea: Port 80 & ...
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4answers
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Make nslookup use specific interface

On my computer I have two network cards. Both are using different Internet Providers service. Both Internet service provider have different DNS server and their IP address are known to me. I want to ...
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1answer
1k views

Static IP address shifting to 192.168.1.251

I have a system with a static IP address of 192.168.1.150. I configured /etc/network/interfaces manually (i.e. without using NetworkManager.) It is a web server hosting three sites. I am having ...
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1answer
216 views

Looking for elegant iproute2 solution for host w/ 2 interfaces on 2 networks and 3 gateways

I've got a Linux webserver with 192.168.0.2/24 assigned to eth0 and 172.16.0.2/24 assigned to eth1. I must not change this. Here's the routing so far: 172.16.0.0/24 dev eth1 proto kernel scope link ...
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2answers
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Network interface preference

How does Linux determine which network interface to use, when both are connected to the same network? Note that this isn't a question on routing. I'm familiar with how that works. This is if, say, I ...
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2answers
1k views

1:1 NAT with several identical LANs

I want to connect several LANs located on remote buildings. The "central" site have a Linux computer running OpenVPN. Each remote site also run OpenVPN. the central site has a LAN numbered ...
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2answers
637 views

OpenVPN uses wrong IP-Address

I've installed OpenVPN on a client (behind NAT-Router) and a VPS server. The tunnel is established. However, ping is only possible from client to server. The server uses its public IP address on tun0 ...
2
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1answer
933 views

Allow IP packet forwarding from LAN to modem via router

In short: I'd like to be able to telnet to my modem from my PC via my router. There is a simple home router on 192.168.33.1. It is running OpenWrt. It has the following interfaces defined: br-lan ...
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1answer
328 views

Firewall/routing rule in Centos for this setup

I have two ethernet interfaces, namely eth0 and eth1. I want to implement an advanced routing rule but I am totally new to firewall/routing rules in CentOS. Here is what I am trying to do: Both my ...
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1answer
366 views

Using source routing (LSRR) - any ideas?

What I want to do is conceptually very simple, but I can't find any information or help about how to go about doing this. Basically, I want to configure my networking to use source routing (LSRR). ...
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2answers
555 views

Policy routing with load balanced ppp connections

This my setup using Debian 6.0. 6. It's role is a proxy server and a load balancer using eight 3G modems. Whenever a ppp connection dials it takes over the default gateway which is ok but it also ...
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0answers
130 views

Unable to access internet if wireless enabled

The following is my route output. eth0 is my wired network and eth1 is my wireless network. Only wired one has access to internet. If I enable wireless, I am not able to access internet, it tries to ...
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2answers
1k views

Xen, bridge and multiple IPs on CentOS

There's a new server that is assigned 5 IP addresses. I want to use Xen to run several VMs with various services. This is my first attempt to install Xen, I use this tutorial as a guideline. Stuck ...
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2answers
455 views

Linux: Is there a IPv6 equivalent to the IPv4 kernel option accept_local?

Since linux kernel >= 2.6.33 the kernel option "accept_local" can be modified: /proc/sys/net/ipv4/conf/${interfaceID}/ accept_local - BOOLEAN Accept packets with local source addresses. ...
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1answer
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iptables forwarding and routing

In fact, this question is about openwrt and CoovaAP, but I guess it's the same in other linux distributions. I've two interfaces, a "wan" and a "wlan" interface. Is there by default any filter, ...
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2answers
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How is the loopback network interface implemented?

The loopback network interface "is a virtual network device implemented entirely in software," according to another question on Unix.SE. But how is this implementation actually accomplished, and how ...
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2answers
390 views

How do I route a spare network interface through an SSH tunnel?

I just bought a Raspberry Pi and I am wanting to route an ad hoc wireless network interface fully through an SSH tunnel that was created using another wireless interface. I want to do this so that I ...
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1answer
550 views

How to provide a “guest LAN” on one ethernet device

I have an always-on machine running Debian/Squeeze with a couple of ethernet ports (it's doing various serverish jobs, including DHCP) and a LAN on each. eth0 is on 192.168.7.* and has access to the ...
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1answer
409 views

Simplest way to set up multiple subdomains to separate VMs running on single host

Problem: I´m planning to set up several virtualized centos, rhel or ubuntu guest machines on a single centos host server (most likely using KVM). Each guest VM is running an instance of a webapp + ...
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0answers
169 views

Traffic getting routed through Apache

for some reason, certain outgoing traffic on my server gets routed to the apache webserver i am running. this problem just started happening. i have the webserver set up to use vhosts, the webserver ...
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1answer
2k views

Redirect http using iptables for an ip range

I have a range of ip addresses (10.13.13.10-19) that I want to redirect all outgoing http traffic to an internal webserver. So if someone in that range tried to access any site, the html from my ...
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2answers
10k views

Linux Networking routing to virtual ip addresses from a different subnet

New to linux networking, had a question about routing to virtual ip addresses from a different subnet. I have three servers (they can all ping each other): A 10.10.51.182 (connected to router ...
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1answer
4k views

Using the Wifi of a notebook via ethernet for another PC

I want to connect a PC to the internet via my notebook, which is connected to a WLAN. The setup should look like the following scheme: PC (eth0) -> Notebook (eth0) -> Notebook(wlan0) -> ...
3
votes
1answer
625 views

Routing through iptables

I have this vpn client that touches the routing table and then keeps watching it to exit if it gets touched. It is the kind of setup needed for an endpoint, such as a laptop. I want to use a small ...
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2answers
1k views

Different domains for multiple VM's on host with one WAN IP

I've got only one WAN IP address bound to KVM host system and multiple VM's with internal IP's, say, 10.0.0.1/28. On the other hand I have multiple domain names bound to host system WAN IP. The ...
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2answers
668 views

Route and “e” flag

k# route -6 Destination Next Hop Flag Met Ref Use If ::/0 fe80::8001 UGDAe 1024 0 0 eth0 [...] What does flag "e" mean?
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2answers
563 views

Having trouble with packets not making it into Fedora 16 Apache [closed]

Background: I haven't done anything with iptables in a few years... I have Fedora 16 running in a VM on VMWare, with my firewall (TomatoUSB) port forwarding to the VM. VM is at 192.168.1.155. I know ...
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2answers
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linux multiple internet connections load balancing with fail handling

I have two ISP connections and need automatic load balancing between them. I also need to handle failed connections (not use one that does not work). First link is a PPTP connection (ppp0), second is ...
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2answers
1k views

Bringing up an interface does not add default gateway to the routing table in Ubuntu

I have this in my interfaces file: auto eth1 iface eth1 inet static address 20.135.251.218 netmask 255.255.255.252 up route add default gw 20.135.251.217 dev eth1 metric 1 ...
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2answers
2k views

CentOS: Sharing WLAN for internet access

I have installed CentOS 6.2 on HP Proliant server. I want to share my USB wireless internet (Tata photon +). I am able to start internet on my server, but when I enable my LAN, I don't have internet ...
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1answer
33k views

Adding two default gateways in Debian interfaces file

This is my interfaces file: auto eth0 iface eth0 inet static address 192.168.1.10 netmask 255.255.255.0 gateway 192.168.1.1 auto eth1 iface eth1 inet static address 192.168.2.10 ...
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2answers
614 views

Adding an ip to a routing table

Is there any way I can add an ip to an interface , but interface route gets created on a routing table other than 'main' routing table in linux? For ex: If I add an IP 10.11.20.10/24 to eth0, it ...
2
votes
1answer
887 views

Routing private network to internet via 2 gateways

I have the current set up for an embedded environment: Embedded Target (192.168.0.200) -----> Virtual Machine (VMWare) (2 NIC's - 192.168.0.2 (Target Port) and 192.168.49.69 (NAT Port to host)) ...
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1answer
563 views

routing between two private networks (NICs)

I have two private networks say: 10.0.1.0/8 and 192.168.0.0/24 I have two machines with two NICs per each machine. machine1 NIC1: 192.168.0.10 machine1 NIC2: 10.0.1.10 machine2 NIC1: 192.168.0.11 ...
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2answers
493 views

SSH connection does not work while browsers do

I have the following network layout: Internet comes true fiber optics to modem. From modem LAN cable goes to router. Since that router wifi signal is weak, a LAN cable goes to another router from ...
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2answers
199 views

How can I use the same IP from the Internet and intranet?

I have an Ubuntu firewall box (Alma), at the office, with a web server on it. It looks like this: [Internet] <-> [DSL Router] <-> [Alma] | ...
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2answers
684 views

Need help with routing

I have set up a Ubuntu server, that I want to use as a router for my local office. The problem is, that I want to make 2 VPN connections, to remote branches, and then I want to route all traffic to ...
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1answer
616 views

Multiple VPN connetions, routing based on country

I want to set up a couple of VPN connections to two different countries, A and B, on my Ubuntu Server. Then I would like to set up rules based on GeoIP to determine which VPN connection should be used ...
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2answers
4k views

How to build a gateway from my Linux OS

I want to configure my Linux so that it will be used as a network router (gateway). Can anybody give me some hints on this? (links are welcome!)
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1answer
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Static route in Centos 6

Here is my route -n output: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 ...
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3answers
1k views

Redirect traffic through vpn on an as needed basis

My problem is really simple yet it sounds complex, but I have zero to none experience with this. I have set up a box using gentoo which has its own semi-static WAN-IP and acts as router for my LAN. I ...
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1answer
496 views

Routing tables and default routes

I have two rules in my routing tables. The default route, which is to the gateway, and a second route which forwards everything in the network segment to * or to no gateway. Is this second rule ...
2
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1answer
825 views

How to setup DHCPD on two interfaces (Angstrom)

I have an embedded system running Angstrom just fine. This platform has multiple uses, one of which is to act as a home router, so it has wireless and wired network interfaces, which work correctly. ...