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

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2k views

Are network and broadcast IPs supposed to respond?

I have a /24 network that is subnetted into a bunch of small chunks. I have recently gone into each router on the network (mostly Cisco) in order to document how this network had been divided. Now ...
3
votes
2answers
416 views

why do Vagrant docs suggest using public IP address 33.33.33.10 for local VMs?

I'm following a tutorial to set up vagrant (a tool to build and configure portable virtual machine images), and it seems that vagrant documentation suggests using IPv4 address 33.33.33.10 to configure ...
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2answers
2k views

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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5answers
2k views

How to route all traffic to one host trough one of two nic's on linux

Setup as follows: One gateway/firewall One switch Two servers behind firewall with 2 NICs each. Each NIC is connected to the switch. The servers are running Ubuntu server. One of the two NICs ...
3
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2answers
2k views

Two DHCP servers on the same network

We are setting up a routing link between the Windows Server 2008 networks of two different buildings in my organisation. Each network uses a different IP addressing scheme (one uses public addresses, ...
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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 ...
3
votes
1answer
5k views

forcing network traffic to route via a specific, non-default interface

I've got a bunch of Linux servers with multiple(3) NICs and associated network interfaces. I'm tripping over a bizarre routing problem, where traffic that should use the default route is not, and ...
3
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2answers
190 views

What happens if one BGP peer only gives me a default while the second peer gives me the full table

Summry question: If ISP A only gives a BGP Default and ISP B gives me the full table, can my router use the information it receives from ISB B to know what IP's are easier accessed through ISP A? ...
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1answer
1k views

Very slow ssh, snmp, telnet network connections but http, sftp are fast

I have a small network with about 8 linux servers, a Cisco 2600 router, and a Cisco 3500XL switch. The router and switch have been configured and working properly for years. About 6 hours ago the ...
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3answers
427 views

Problem with connecting two different networks

I have two networks: 192.168.13.0/24 (blue) and 192.168.15.0/24 (green). Computer A is connected to the 13-net, only. Computer B has two interfaces, one in each network. There is third computer that ...
3
votes
1answer
101 views

2 NICs, same subnet, different default gateways

I have a switch on which 4 modem/routers and 2 servers are connected. Each server has 2 processes running and 2 NICs connected. What I want is that each process is routed out of either one of the ...
3
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2answers
2k views

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 ...
3
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1answer
465 views

Linux: force source address for packets to locally bound IPs

I have 10.1.1.1 and 10.2.2.2 bound to eth0. # ip address show dev eth0 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 04:01:05:ff:42:01 ...
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votes
3answers
3k views

Copy/Mirror traffic to WAN interfaces without “iptables tee” support

I want to copy every outgoing packet to others WAN interfaces but my iptables (v1.2.7) has not TEE target support. I wonder if there is another way (maybe using iproute2 or ebtables) to copy every ...
3
votes
2answers
2k views

custom route not working on windows

My windows laptop is directly connected to 192.168.1.0/24 (wireless lan). I access 10.21.0.0/16 though a router that is connected to both networks. The routing works fine with this configuration. I ...
3
votes
1answer
753 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. ...
3
votes
1answer
176 views

Network Design and Implementation

I am currently designing the network in my office, which is relatively small now but it plans to grow very fast. The design is pretty much done, the problem is occurring during the implementation. So ...
3
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3answers
578 views

identify a router that cuts certain port

Is there a way to identify which particular router between me and some server blocks connections on certain port? I am in a hotel in Thailand, where they have recently changed some settings in their ...
3
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3answers
619 views

2 BGP Upstreams, One sending default route, another Full Table

We have 2 upstreams ISP A and ISP B. ISP A (10Mb/s) is our main upstream with good bandwidth. It sends us default route over bgp. ISP B (2Mb/s) is our backup upstream with a small bandwidth, but it ...
3
votes
1answer
421 views

Does ESXi 5 have a “routed IP” feature like Xen?

I have a dedicated server that I would like to use ESXi 5 on. I previously had Xen and it worked great. Initial network configuration was a bit confusing. The problem I have is the hosting company ...
3
votes
2answers
310 views

Multiple IPv6 routers in a local network

I'm setting up some servers that will run virtual machines using IPv6. The network topology is something like this, where the br0 interfaces are virtual: 2001:db8:fedc:aaaa::/64 ...
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votes
3answers
2k views

How can I prevent OpenVPN from clobbering local route?

I have a local network on 192.168.1.0 with netmask 255.255.255.0. When I connect to a VPN though OpenVPN (as a client), it pushes a route for 192.168.1.0 that clobbers the existing one, making my ...
3
votes
4answers
2k views

Failover routing between 2 gateways

I have 2 routers in a cabinet and would like to setup fail over between the two for our servers sort of like BGP but not BGP :). I need to setup the system to realize gateway 1 is (down) or under ...
3
votes
1answer
2k views

Setting up linux routing

The system I'm trying to set up has an IP address 172.31.2.1. Its default gateway is 172.31.254.1. This works fine, and I can reach anything the gateway allows me to go to (172.31.0.0/16 + ...
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4answers
15k views

Routing and remote access VPN setup

I am trying to set up VPN using routing and remote access. I've tried two configurations, one using a single network card, and one using two network cards. I can connect through my VPN and get ...
3
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5answers
259 views

Router limits network performance but its CPU load isn't 100%

I'm using a PC Engines APU device running FreeBSD as a NAT router. The setup is very usual: one WAN connection and one LAN connection. Theoretically, WAN connection is 800/40 Mbit/s and the LAN one ...
3
votes
1answer
508 views

Internet routing table breaks 512,000 routes [closed]

Looks like with all the mass IP grabs as well as subletting of space, things have finally hit the 512K mark. Anyone on the raw end of an upstream router that ran out of route space? How do most ...
3
votes
1answer
2k views

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. ...
3
votes
3answers
7k views

Routing WIFI and LAN for specific traffic

I have two network devices aboard my macbook pro: WIFI (en1): Used for general traffic. Connects to an ip of 192.168.19.* via DHCP LAN (en0): Used for specific traffic. Connects to an ip of ...
3
votes
2answers
1k views

View Infiniband routing table generated by OpenSM?

As I understand it, the subnet manager of an Infiniband network calculates the best routes between each pair of nodes on the network and provides these routes to the nodes when they want to ...
3
votes
4answers
266 views

Add a server between router and switch (production)

I have a small office network basically like below, there are more router/pc connected in S1. As you can see, the router is doing job of DHCP, DNS. but now I wish to add a Linux server between R1 and ...
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votes
2answers
5k views

How does F5 GTM work?

The F5 GTMs automatically reroute users to one of the available datacenters should one fail. How does it do this? For instance the F5 could act as a DNS server and simply serve a different IP to ...
3
votes
1answer
3k views

How can the route between two private IPs go via public IPs?

I'm trying to understand what this output from traceroute means. I changed the IP addresses for privacy but retained the public/private IP range distinction. traceroute.db -e -n 10.1.1.9 traceroute ...
3
votes
2answers
455 views

Outbound IPv6 Trafic Fails

My hosting provider has supplied me with global static IPv6 for my machine. It appears that auto configuration has been successful and I can successfully ping my machine and tracepath6 appears to ...
3
votes
3answers
20k views

Source-based routing on Cisco 3750 switch?

I have this Cisco 3750 switch which handles many VLANs. It has an IP interface on some of them, and it does routing for those computers connected to those VLANs which use the switch's IP addresses as ...
3
votes
1answer
6k views

Ubuntu Karmic: purpose of route table entry for 'link-local'?

I'm wondering what is the purpose of a routing table entry named 'link-local'. root# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface ...
3
votes
1answer
889 views

Rotating outgoing IPs using iptables

I am trying to rotate outgoing IPs using iptables. I want to rotate outgoing connections between three IPs, one by one. Here is what I'm doing with iptables: root@server:~# iptables -t nat -I ...
3
votes
1answer
65 views

Routing table configuration

Suppose having an routing table in which the default-route is missing can a router work without a default-route or the table is incomplete? and having these two entries is also legit or there is an ...
3
votes
2answers
171 views

Preventing endless forwarding with two routers

The network in quesiton looks basically like this: /----Inet1 / H1---[111.0/24]---GW1---[99.0/24] \----GW2-----Inet2 Device ...
3
votes
1answer
2k views

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 ...
3
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: ...
3
votes
2answers
1k views

SSTP on Windows 2008 cannot ping in either direction

I have the following setting going on. Server: Configured windows 2008 server as AD, DHCP, DNS, CA and RRAS. To make long story short, RRAS can accept SSTP connection and clients get connected fine. ...
3
votes
2answers
3k views

OpenVPN redirect-gateway does not work on Windows 7?

i have set up openvpn, and it works. pinging from client to server and backwards works just fine. but now i wanted to redirect all the clients traffic through the vpn. so i did the following steps as ...
3
votes
2answers
700 views

Prevent a single host from consuming entire bandwidth?

We have a linux router providing internet connectivity to several PCs. It's currently using shorewall to help make the iptables setup easier. Is there a way I can set it such that any individual host ...
3
votes
4answers
116 views

Only able to use the first IP in a range from ISP

Right now I have a subnet of 16 IPs. I want all of the ips to be "owned " by my firewall. I have a watchguard firewall statically configured with X.X.X.225 and has X.X.X.226 - 238 as Secondary IPs. ...
3
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1answer
737 views

Difference between “traceroute” and “traceroute -U”

The manpage of traceroute says that the "-U" parameter (UDP probing) is the default, but I'm getting different results every time. With "-U": traceroute -U www.univ-paris1.fr traceroute to ...
3
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5answers
1k views

Do I need a VPN to secure communication over a T1 line?

I have a dedicated T1 line that runs between my office and my data center. Both ends have public IP addresses. On both ends, we have AdTran T1 routers which connect to SonicWall firewalls. The ...
3
votes
2answers
356 views

IP Forwarding and traffic shaping

Is there any way to forward packets from network A to network B (just like a router) without changing source IP Address (and vice versa, from network B to network A) and also enforcing traffic shaping ...
3
votes
1answer
796 views

Domain Based Port Forwarding with VLAN routing [closed]

At my new workspace I want to setup a network that enables me to deploy my web development work on Dev, Test and Accept servers (VMs) with (controlled) access from outside the network - based on ...
3
votes
1answer
86 views

How can I tell if a host is bridged and acting as a router

I would like to scan my DMZ for hosts that are bridged between subnets and have routing enabled. Since I have everything from VMWare servers, to load balancers on the DMZ I'm unsure if every host is ...