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

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Why does ifconfig reset the default gateway route?

In FreeBSD, an ifconfig call seems to delete the default gateway route, even when given the same IP-address (e.g. when updating the netmask only). Is it a bug or a feature? As fas as I remember Linux ...
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2answers
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Is it possible to use proxy-arp back to the same interface?

I have a WiFi Access Point connected to a Linux Router. The Router is itself connected to the Internet. For multiple reasons (mostly to control security and quality of service), I want to force all ...
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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: 192.168.200....
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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: ...
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3answers
288 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 ...
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1answer
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How can I route different traffic over different interfaces (routes) by protocol?

I have two different WAN interfaces in a Linux (iptables) router. How could I achieve a situation where different traffic is routed over different interfaces, depending on the protocol (destination ...
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2answers
646 views

IPv6 and NAT, routing to multiple ISPs

Currently I have a nice setup using private IPv4 address space and uplinks from two ISPs to the Internet. Thanks to NAT I can just take down one of the interfaces and the Internet access is still ...
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1answer
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Router advertisement for ipv6 is advertising link-local adress

I have the following situation: I configured a FreeBSD 9.1 machine as the endpoint of a heartbeat SixXS tunnel on a gif0 interface. It works so far, and I can ping6 via IPv6. I assigned to another ...
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“route add default -iface em1” in rc.conf on FreeBSD

I have two NICs on my FreeBSD server, which are set up like this in rc.conf: ifconfig_em0="10.0.0.1 netmask 255.255.255.0" # LAN NIC ifconfig_em1="DHCP" #...
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2answers
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Policy based routing

I found very good article on load balancing at http://www.diegolima.org/wordpress/?p=36.. I could not implement it though as my requirement is slightly different from pure load balancing. We have two ...
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4answers
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Prevent SSH connection lost after logging into VPN on server machine

I encountered an issue that I can't deal with. When I'm logged onto an VPS over SSH and try to estabilish VPN connection on that VPS, the SSH connection between VPS and my machine get lost. I assume ...
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1answer
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W7 routing - traffic not going to default gateway

I have a really strange Windows 7 IPv4 routing issue that I can't get to the bottom of. The summary of the issue is that the default gateway is set to 192.168.254.253, but that it is actually using a ...
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2answers
795 views

IPv6 routing problem

I've received a native IPv6 /64 subnet from my server provider, but I can't get it to play the way I want it. I'm running virtual machines, and I want them to have their own public ip(s). Let's ...
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2answers
462 views

Choosing nearest Server across the globe?

i want 3 dedicated servers: in USA, Europe and China. They all run exactly same website. I want to setup them so, that particular user will automatically talk to the nearest in network sense instance ...
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4answers
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Dynamic subdomain routing

I asked this question over at stackoverflow, but got very few views: http://stackoverflow.com/questions/2284917/route-web-requests-to-different-servers-based-on-subdomain Perhaps it's more applicable ...
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How do I tell OS X's implementation of Bonjour/ZeroConf which network to use for mdns?

I have four networks on my machine: 192.168.20.0/24 wired (connected only at work) 192.168.20.0/24 wireless (connected only at home) 192.168.132.0/24 VMWare's NAT 192.168.238.0/24 VMWare's host-only ...
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4answers
835 views

Route IP Traffic Based on Process to Different Default Routes / Interfaces

I'm trying to determine if it is possible to selectively route IP packets from a process or process group through a specific interface while all other packets are routed through another interface. ...
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1answer
633 views

Load balancing network traffic using iptables

I am trying to load balance traffic from internal LAN on a linux router having two gateways. Initially I went for the iproute implementation which didnt balance the load as expected, reason being that ...
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1answer
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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 ...
5
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1answer
4k 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 0.0.0.0 255.255....
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1answer
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OpenVPN server cannot ping client IPs

I have flashed a router at two separate sites with DD-WRT firmware and setup OpenVPN on both. once connected the client can ping computers on the servers LAN however the server cannot ping IPs on the ...
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1answer
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Windows Server 2008 R2 RAS VPN: access server on internal interface ip

short question: I'm usually a linux admin but need to setup a Win2k8 R2 server for a student project. The server is running as VM on a root server and has a public internet IP assigned. Additionally I ...
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1answer
66 views

Overcome asymmetric routing while migrating between sets of ISPs

We are migrating from one set of addresses to another set, both /24, and trying to minimize any down time during the migration. Ideally we'd run both for a period of time as we shut down the old ...
5
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1answer
215 views

timing issue after route add/delete (route not used)

I have an application that is running a raw IP socket, destination of this socket is governed by routes installed via the 'ip route add' command. These routes can change during the lifetime of a ...
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3answers
506 views

Is Internet routing (BGP) fully automated?

If all the routing tables on the Internet would be erased simultaneously, will the routers be able to rediscover them automatically? I'm having an argument with a colleague who says that the RIPE ...
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2answers
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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.
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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 ...
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6answers
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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 ...
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2answers
924 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 ...
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2answers
825 views

IPv6: differences between “routed prefix” and “link prefix”?

What are the exact differences between "routed prefix" and "link prefix" for IPv6?How do these differences in a wireshark-Trace? (if you observe a Host with an assigned "routed prefix" or a Host with ...
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2answers
203 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 in ...
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How ISPs will assign IPs /subnets for end users in IPv6

Consider two scenarios: The end user has a simple computer, dual-stack The end user has a LAN behind a dual-stack router How will ISPs differentiate each one of these kind of users in IPv6? An ...
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2answers
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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 ...
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4answers
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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 ...
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3answers
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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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2answers
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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 ...
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4answers
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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
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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 ...
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1answer
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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. ...
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2answers
370 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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3answers
563 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 ...
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4answers
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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 ...
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3answers
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How to enable traceroute in linux machine

I'm working on something in the transport layer and after i ran our custom policies for securing the policies i'm not able to do traceroute from the linux machine. root@keystone-evm:~# iptables -L ...
4
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2answers
600 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 ...
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2answers
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ip route show src field

I read the man page of ip and still do not understand what src is and I could not find much documentation. Please, if you can explain it thoroughly or point to some link it a good answer.
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1answer
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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) ...
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1answer
162 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 ...
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1answer
288 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
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1answer
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pfSense router on a LAN with two gateways

I have a LAN with an ADSL modem/router on it. We have just gained an alternative high-speed internet connection at our location, and I want to connect the LAN to it, eventually dropping the ADSL. I'...
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1answer
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Routes bound to virtual interfaces, Debian, and how to determine specifics, after the fact

I've recently begun a new job, and have inherited an existing infrastructure with a lot of issues. One of the issues is that the previous admin added static routes to some servers, bound to virtual ...