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Questions tagged [router]

A device that connects two or more networks and is capable of forwarding data packets to a destination based on information contained within a packet and internal routing tables.

Routers are devices that connect networks and make decisions on where to send incoming data packets, based on the address information contained in the packet and internal routing information.

The most common form are SoHo routers, which connect home or small office networks to the internet and provide routing for all devices on the home/office network. More advanced routers connect large office networks, and at the high end of the scale routers connect large segments of telecommunication networks all over the world at high speed.

Routers are not limited to TCP/IP networks, they can be found in any kind of network.

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Experiences with BIRD for BGP?

We're currently using Quagga with Debian Linux to run a full table BGP router. The set-up has been dead simple up to now, but we've come to a point where I have to reconfigure the router quite a bit, and want to tighten things up. I've never really…
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NAT: If two hosts initiate a connection to the same IP:PORT, with the same source PORT, how does the router handle it?

I was just thinking and that idea came to my mind. Let say I have hosts A and B inside my local area network. I have a Router, and a host C in the internet. I know that when initiating the connection, the source port is chosen randomly, but what…
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Can't communicate between lan ports on openwrt router

I've got a WBMR-HP-G300H Buffalo Airstation router on which I've installed the lates OpenWRT software. All is working well (ADSL, WIFI etc) except for one niggle. I can't communicate between lan ports. i.e. if I have one computer connected on lan…
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How to prevent or block other DHCP servers?

Is it possible in a managed switch such as a 3com 4500 or a HP Baseline PWR-Plus type switch to block DHCP from being served through specific ports, or all except 1 port? I have a DHCP server for example plugged in to port 1, I need that to continue…
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Limit ICMP Per Source IP with IPTables

I have mistakenly thought that the limit module is per source ip, but it appears to be based on all requests: 577 36987 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmp type 8 limit: avg 3/sec burst 5 46 3478…
Kyle Brandt
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Using iptables to block ALL outgoing traffic from one NIC?

I must pretty bad at Googling as this seems like a very basic question but I can't seem to find the answer anywhere... and man iptables is a very long read! I have two NICs - eth0 and eth1 - on a linux box and I want to block ALL outbound traffic…
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SOHO - throttle bittorrent traffic from problem users

I manage the network in a small office (SW dev is my "real job"), and there are a couple of users who beat the hell out of our internet connection by running bittorrent. Between the almost crippling effect on the upload side (20Mbps) and the…
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Configure Juniper M320 as Ethernet/STM transparent converter

There is Juniper M320. We need to move ALL the traffic from one port to another. Everything that comes to one port goes to another and vice versa. No snooping or any other processing is required. One port is going to be Ethernet and another one is…
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How do you manage your Linux iptables configuration on a machine acting as a router?

I have a couple Linux machines that act as routers/firewalls for my networks and I have a script that runs all the iptables commands to set my rules. This seems to me like a really silly way to do it though. How do you do this? Is there a program…
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Getting an IP's MAC address from behind a router

I want to know, if possible, how to get a MAC address of an IP address if I am behind a router. I tried doing a ping to the IP and checking the arp table, but the only entry is the router's MAC. Any ideas? Thanks for reading.
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Using dd-wrt Dynamic DNS client with CloudFlare

I'm trying to configure Dynamic DNS client on my router with dd-wrt (v24-sp2) firmware so it would dynamically change IP address in one of the DNS records. Unfortunately I encountered a problem… Here is an example request from their ddclient…
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Inexpensive, Reliable Captive Portal

I do some wifi hotspot installations, and a new client recently asked me if it would be possible to force users to his website when they first open their browsers. After some Googling I figured out that this is "captive portal". It's a free wifi…
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Could someone explain why traceroute seems to be skipping a router on my network?

This is probably a very basic question, but I'm hopping someone can explain what's going on to me. I configured our wireless router at work to connect to directly to the router that provides our internet connection. I set the wireless router up with…
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Cisco router for educational purposes

I want to buy a Cisco router to use on my home network. I'm just hoping to get a unit that is not too old and is not a SOHO model. I want to run the latest Cisco OS just to learn how Cisco does things. I would use it to divide my network into two…
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Slow down individual connections passing through a Linux router?

We have a Linux server acting as a router/firewall for our office. Occasionally someone will upload a large file that takes up all our bandwidth. I don't want to implement any complex rules or traffic shaping, but I'm wondering if there is a way to…
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