the process by which data packets on communication networks are forwarded into the direction of their ultimate destination by routers.

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330 views

Using Internal or External IP for File Transfers in Data Center?

I am pretty sure I know the answer to this, but 2 technical people in my organization cannot agree, so I'm putting this on ServerFault to get a final opinion. We have a relatively simple set up in a ...
4
votes
4answers
4k views

Use specific interface for outbound connections (Ubuntu 9.04)

I have two ethernet interfaces in my computer, which is running Ubuntu 9.04. Both interfaces sport static IPs, but use separate gateways. My /etc/network/interfaces file looks something like this: ...
4
votes
6answers
5k views

How do I point my browser to a specific NIC on my machine

I am on a local area network that has no external access to the internet. However I have been tasked to find a way to allow certain machines to access the web (HTTP, HTTPS, etc) via a wireless card ...
4
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2answers
2k views

IP Routing - how does it work again? [closed]

Can someone explain how IP routing works to me? E.g. if I ping 123.123.123.123, how does each router know which way to go as shown in a traceroute dump.
4
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2answers
757 views

Routing selection: specificity vs metric

I understand that Linux chooses the most specific route to the destination when it does routing selection. But what about a route's metric? Does it have a higher priority than route's specificity? A ...
4
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2answers
807 views

Blackhole route private intranet traffic

I have a private network with a handful of Linux routers all route sharing via OSPF. How do I blackhole private network ranges that I don't have routes for? In other words, I want to be sure I NEVER ...
4
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2answers
184 views

Is this IPv4 and subnet combination public or private? [duplicate]

Possible Duplicate: How does IPv4 Subnetting Work? I thought I understood this but I am momentarily confused. Here is an example: Are all IPv4 addresses from 192.168.0.0 to 192.168.255.255 ...
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3answers
3k views

How can I reroute a sub-domain to localhost + port number?

I have several web applications running on my developer machine. They mimic our production web applications which are hosted on sub-domain. For example, consider: api.myserver.com - is mimicked by ...
4
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2answers
9k views

Is there a way to stop relaying network traffic through VPN?

I have been experimenting with VPN lately, and I managed to get it running on W7 PC. The problem is, though, that as soon as someone connects to my PC, the internet traffic from their PC is routed ...
4
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4answers
2k views

Determine switches between devices on LAN

I'm on a network where most devices are DHCP. If I have a few switches between device A and a DHCP server, how can I find out what they are? traceroute just gives me 1 hop, regardless of the number ...
4
votes
3answers
4k views

Cisco - NAT causes nslookup to return local IP

A little background: I have a server on my LAN that is statically NAT'd to its public IP in my Cisco 871. The rest of the same local subnet is statically NAT'd to a different Public IP, in order to ...
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4answers
4k views

Why would certain network switches stop working, others are fine?

I am sure many of us are used to (or have experienced) the routine (or at least occasional need) of having to reboot (or power cycle) a cable modem, dsl modem, router or hub/switch. However, I ...
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3answers
2k views

Dead gateway detection on linux

I have to setup dead gateway detection on a linux box with three network interfaces. The only guides I have found so far on the topic imply patching the kernel, which we are not very keen to do. Is ...
4
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2answers
1k views

Bypass openvpn for particular ip

My desktop machine runs Trisquel GNU/Linux 6.0 (which is basically a libre version of Ubuntu 12.04), and I use OpenVPN to connect to a commercial VPN provider for internet access. It currently routes ...
4
votes
1answer
984 views

BGP path prepended route not listed anywhere

We have a simple multi-homed setup with two routers that advertise our AS to two ISP. The second ISP (ISP B) is only used for backup when ISP A goes down, so we prepended our AS 3 times on this route. ...
4
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2answers
289 views

Impact of MTU on IP packet fragmentation and reassembly

Let's say computer S (sender) sends some IP packets to computer R (receiver). Between S and R, there are 6 networks, divided by 5 routers. So the IP packets leave R, go through network 1, pass router ...
4
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1answer
42k views

Two network interfaces and two IP addresses on the same subnet in Linux

I recently ran into a situation where I needed two IP addresses on the same subnet assigned to one Linux host so that we could run two SSL/TLS sites. My first approach was to use IP aliasing, e.g. ...
4
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3answers
518 views

LAN and WAN at the same cable?

Can I connect LAN and Internet using the same cable? LAN computers ------\ Ubuntu server ------Switch ADSL Router --------/ I want to make LAN computers 192.168.0.2-50, server will have real ...
4
votes
4answers
5k views

OpenVZ multiple networks on CTs

I have Hardware Node (HN) which has 2 physical interfaces (eth0, eth1). I'm playing with OpenVZ and want to let my containers (CTs) have access to both of those interfaces. I'm using basic ...
4
votes
2answers
482 views

EIGRP neighbors flapping

I have a EIGRP topology set up in GNS3. It looks like this: The neighbor relationship between R7 and R8 is constantly flapping and I cannot figure out why. Hello timers and time delays are all set ...
4
votes
3answers
229 views

Routing table hits?

With iptables -L -n -v, you can get the number of times each firewall rule has been applied, which is very useful in debugging. I'd like to know if there's a similar way to find out how many times a ...
4
votes
1answer
140 views

Linux as router - How can I determine which route to use (depends on different source addresses)

I have a Linux server and I used it as a router, which has two network interfaces. I use eth0(10.76.8.60/24, 10.76.8.50/24, router: 10.76.8.1) to connect to the network, and eth1(192.168.1.1/24) ...
4
votes
1answer
132 views

Massive packet duplication

Short Version: We've had a problem with a particular server receiving massive duplicates of packets. After much fault finding we found the problem was caused by a switch sending my packet out every ...
4
votes
1answer
224 views

routing table vs PF precendence

I am wondering when a packet reaches an interface and I have some PF rules, which gets checked first, the routing table or the ruleset? ext_if = "em0" int_if = "em1" localnet = $int_if:network ...
4
votes
3answers
3k views

linux vlan routing

I've got this network topology: network 192.168.100.0/24 vlan 100 network 192.168.200.0/24 vlan 200 one ubuntu server(2 vlans on 1 ether) eth0.100 (ip:192.168.100.10/24) eth0.200 (ip: ...
4
votes
1answer
1k views

MULTI: bad source address from client - any one-off solutions?

Setup: I have the an openvpn client/server setup (config files at bottom), and I get the infamous MULTI: bad source address from client [192.168.x.x], packet dropped message at server. The server has ...
4
votes
4answers
756 views

Why on linux machines, any packets do not pass except icmp, but correctly pass on windows

There is a cluster on proxmox. In a cluster have vm - configured router (pfsense). In the our net have Windows and Linux machines. There is the problem: Windows-machines have access to the internet, ...
4
votes
1answer
906 views

New KVM guests cannot access outside LAN

I have a KVM host (at 192.168.0.10) that currently has one working KVM guest (at 192.168.0.12). On attempting to install a new KVM guest today, I reached a problem where the network on the new guest ...
4
votes
2answers
1k views

Routing to proxy and code injection into files served on local network

I'm trying to set up an Open Device Lab. This question focuses on the network routing of and injection of code into the responses to requests made by the test devices. I want people to be able to ...
4
votes
2answers
131 views

Add Route for machine in same DC

My routing table on my machine with IP of 46.84.121.243 currently looks like this - Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 ...
4
votes
2answers
2k views

Forward differing hostnames to different internal IPs through NAT router

I have one public IP address, one router and multiple servers behind the router. I would like to forward differing domains (All using HTTP) through the router to different servers. For example: ...
4
votes
4answers
7k views

How to make routes on a windows 7 laptop persistent?

I have a number of (windows 7) laptops that normally connect via wireless. We also have a wired network for special purposes. When one of these laptops plugs in to the wired network, at the moment, it ...
4
votes
3answers
7k views

How to configure remote access to multiple subnets behind a SonicWALL NSA 2400

I have a client that uses a SonicWALL NSA 2400 as their firewall. I need to setup a second LAN subnet for a handful of PC. Management has decided that there should be a second subnet even though ...
4
votes
3answers
2k views

two gateways / two providers with different ips

I want to route packets coming in on eth0 back over eth0 and the ones coming in to eth1 back over eth1. I don't care which gateway is used for outgoing connections. If i just enter two gateways in ...
4
votes
1answer
147 views

Can I have different routing table for different users?

My Linux machine have two accounts. I want to set different default gateway for the different accounts. How can I do this, if it is possible?
4
votes
1answer
338 views

Possible to have DHCP hand out different DNS server address when using different tunnel?

We have several ASA 5505 deployed. Currently, we have a setup where the local ASA is answering DHCP queries and is configuring clients with two DNS servers: our DR site DNS server (we use AD) and a ...
4
votes
4answers
389 views

Monitor an internet link to a remote host

I have a Debian Wheezy server running Xivo (let's call it A), this server has 2 interfaces: eth0 and eth1 . There is no default gateway and only a few servers are statically reached from A. eth0 has ...
4
votes
1answer
584 views

libvirt guest cannot reach outside world

My server connects to the public internet via eth0 (50.131.xxx.xxx). The same server connects to the LAN via eth1 (192.168.138.1 on 192.168.138.0/24) On the same server, I run libvirt, which created ...
4
votes
3answers
7k views

Windows Server 2008 Ignores Persistent Route With Lower Metric

I have three Windows Web Server 2008 SP2 machines on a 10.100.20/24 subnet. I need to setup a persistent routing rule so that outgoing traffic to the same subnet goes through a hardware load balancing ...
4
votes
1answer
964 views

Quagga keeps announcing down routes

I have set up BGP on two routers using qugga. When I down the interface that holds the IP block that I am advertising zerba removes the route from its table but bgpd keeps advertising it. I can see ...
4
votes
2answers
5k views

Linux port-based routing using iptables/ip route

I have the following setup: 192.168.0.4 192.168.0.6 192.168.0.1 +-----------+ +---------+ +----------+ |WORKSTATION|------| LINUX |------| GATEWAY | +-----------+ ...
4
votes
7answers
2k views

Dropped IP traffic with a multihomed server

(Before getting into details, I'm presenting this problem with Apache and SSH as an example, but this is not specific to TCP traffic, it is the same problem with both TCP and UDP based protocols.) I ...
4
votes
1answer
1k views

blocked.domain.gstatic.com - Where could this blocking be?

As of this morning we were having serious issues (partially loaded site with no functionality) accessing Google Drive which we use heavily. Other websites seemed to work fine. This is happening on ALL ...
4
votes
1answer
3k views

Strongswan VPN Established but no Packets Routed

I'm setting up a VPN using strongSwan between a Linux instance on an Amazon EC2 instance and a remote network via its Cisco concentrator. I need to route packets from the Linux instance itself a ...
4
votes
1answer
3k views

Fortigate VPN Routing issue

I have 200B Fortigate unit with 2 internet WAN connections. I also have a remote site which I'm connected to via IPSEC VPN through WAN1. This site has only one GW IP address. I'd also like to setup a ...
4
votes
2answers
6k views

Routing between two routers with static routes

I have a Draytek 3200 router and a pfsense rackmount router that I am trying to get to route to each other. I have a subnet on each router and a subnet for the link between, as shown here: As it ...
4
votes
1answer
433 views

ping request not forwarded in one direction

Edit: I solved my issue just as I was finishing this insanely long post. I had simply not enable ping reply in my windows firewall which is why I could not ping a computer on network 0 from network 1 ...
4
votes
1answer
3k views

Are Link-Local routes necessary (IPv4)?

I noticed in my routes output in RHEL6 (and most 2.6.x series Linux), for every interface I see the creation of the following route in my kernel routing table: 169.254.0.0 0.0.0.0 ...
4
votes
1answer
23k views

How do I route between interfaces in PFsense?

I have a PFsense router which divides a single WAN connection into three NAT networks on three interfaces: LAN, OPT1 and OPT2. This allows me to segregate my network so that computers on the OPT1 and ...
4
votes
1answer
4k views

Single m0n0wall - Two LAN Subnets - How To Setup

I have two LAN subnets that I need to link together they are 192.168.4.0/24 and 192.168.5.0/24 There is a m0n0wall running on 192.168.4.1. It's LAN connection goes out to our network switch, and it's ...