IP - Internet Protocol, the most commonly-used set of rules for dispatching data across a large computer network.

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35
votes
7answers
20k views

What is “anycast” and how is it helpful?

I'd never heard of anycast until a few seconds ago when I read this SF post. The wikipedia entry on it is quite formal and doesn't really evoke a mental picture of how it would be used. Can someone ...
27
votes
5answers
8k views

Debugger for Iptables

I'm looking for an easy way to follow a packet through the iptables rules. This is not so much about logging, because I don't want to log all traffic (and I only want to have LOG targets for very few ...
11
votes
4answers
11k views

How to make Postfix use another IP address?

I'm using the Postfix mail server and I have 6 IPs available. I'd like to use another IP for the Postfix mail server for sending mail than the web server uses. How can I do this? My postfix version ...
16
votes
7answers
16k views

Force local IP traffic to an external interface

I have a machine with several interfaces that I can configure as I want, for instance: eth1: 192.168.1.1 eth2: 192.168.2.2 I would like to forward all the traffic sent to one of these local ...
5
votes
4answers
4k views

Apache virtual host based on *source* IP

Is it possible to configure Apache for different virtual hosts based on the source IP? (i.e. same interface, same hostname, but two different virtual hosts, with different content, based on source ...
3
votes
1answer
178 views

My visitors %20 percent can't reachable to my web site

i have dedicated web server and also i hosting www.btgmaslak.com web site. I'm facing a problem about 1 days. My visitors about 20 percent can't reach my web site. I thing this problem occurs because ...
67
votes
4answers
70k views

What's the difference between ip address 0.0.0.0 and 127.0.0.1?

I do know that 127.0.0.1 ~ 127.255.255.254 are the loopback IP addresses for most modern operating systems and we could use these IP addresses to refer to our own computer. But what's 0.0.0.0? It ...
16
votes
8answers
10k views

What is the network address (x.x.x.0) used for? [duplicate]

It appears to be common practice to not use the first address in a subnet, that is the IP 192.168.0.0/24, or a more exotic example would be 172.20.20.64/29. The ipcalc tool I frequently use follows ...
7
votes
2answers
609 views

Is there anything I can do about someone who has pointed their domain at my ip?

This is kind of a weird request. For some reason whoever owns safeandbuy.com has pointed their domain at my IP address. The reason it's a problem is that I'm having all kinds of crawlers that are ...
6
votes
3answers
3k views

Find IP address of a device?

Open question: How to find the IP address of a device? As I understand, there are no guaranteed methods that work always, but there's a hundred approaches that work in specific situations, and I'd ...
1
vote
2answers
5k views

Centos: multiple IP addresses

I just bought 10 extra IPs from my host. How do I point these at my CentOS 5 server?
7
votes
1answer
2k views

Can the value for a NS record be an IP address?

Until today I was used to believe it couldn't. From this page The name field can be any of: A Fully Qualified Domain Name (FQDN) e.g. example.com. (ends with a dot) An unqualfied name ...
5
votes
2answers
1k views

IP Routing - how does it work again?

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 trace route dump.
0
votes
5answers
453 views

Many domains/sites hosted on same server, CNAME alternatives to avoid writing same IP in DNS?

I have many sites (each one with its own domain) all on the same cPanel hosted server (let's say server IP is 1.1.1.1 and server main domain is myserver.com) All these domains use third party DNS ...
29
votes
3answers
35k views

What is the difference between unicast, anycast, broadcast and multicast traffic?

I have never had the privilege of working in an environment that required complicated routing or if it did require it, it was handled upstream of me. I've always used very simple static routing ...
116
votes
5answers
161k views

MySQL: Bind to more than one IP address?

Is there a secret way to bind MySQL to more than one IP address? As far as I can see the bind-address parameter in the my.cnf does not support more than one IP and you can't have it more than once.
9
votes
4answers
54k views

How to route different traffic thru different network interfaces (in Windows)

I've searched for details on how to do this but I've been unsuccessful - I wondered if someone could offer up some advice. So, let's say I have 2 network cards (LAN and 3G in my instance), both ...
19
votes
3answers
23k views

How do I block specific IPs and IP ranges in IIS7?

I'm trying to block various IP addresses from every site that I have hosted from an server running Windows 2008 and IIS7. I've found various information about how to do this using Deny rules from ...
4
votes
5answers
4k views

IP/Process based bandwidth usage stats tool for linux

I'm looking for a simple tool to report server bandwidth usage based on IP/Process. The reason for that is one of our servers is "bleeding" bandwidth and there is a need to find out where it's going. ...
5
votes
1answer
2k views

Bind process or user to specific IP (Linux)

I have 3 non-root users on my server, and I want to give to each of them the different IP addresses (I have multiple IPs on one network inteface). For example, user1 will have 192.168.1.2, user2 - ...
11
votes
2answers
1k views

Multiple IP addresses per NIC

How can I have multiple IP addresses assigned to a single NIC? I remember doing this on Unix way back when. Can it be done on Windows?
10
votes
6answers
18k views

Why was my ping answered by a different IP address than the one pinged?

While trying to setup a MSSQL clustering solution, I am running into a problem that is outside of my expertise that is related to networking. I was trying to find a free IP to used for my node. I ...
2
votes
1answer
575 views

How come I can't redirect TCP ports on this wireless router?

I am configuring a router to redirect TCP port 5900 (yes, this is for VNC) to a specific IP address on the network. Here is what I have: From a local computer on the same network, I can telnet to ...
2
votes
3answers
1k views

In Apache, is there a way to limit the number of new connections per second/hour/day?

To clarify, I do not wish to limit the number of simultaneous connections, nor do I want to limit the number of HTTP requests. I only want to limit the number of NEW connections per IP. I want to do ...
2
votes
4answers
5k views

What are the implications of expanding an internal subnet mask?

Our network is currently working on a 192.168.0.x subnet, all controlled through DHCP, except for the few main servers who have hard-configured IP address settings. What would I kill if I changed the ...
0
votes
2answers
3k views

How to route UDP traffic from one public IP (linux) to another public IP(Windows)

I want to prevent direct access of my Windows Machine and want to expose some programs running on it via my Linux Machine (which again is accessible by a Public IP). Is there a way where-in I can ...
-2
votes
1answer
76 views

is it possible to make some vps with a single share ip using linux? [closed]

I want to make a vps center to provide vps for users.I want to assign ip to vps BUT I wonder is it possible for vps centres to assign share ip to all vps? like share hosting
7
votes
4answers
431 views

How to know what user belongs to what ip on debian

is there a way to get an overview of users logged in on my server and the ip they are connecting from ? I have the IP already, I want the user that is associated with it :)
4
votes
2answers
343 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 ...
3
votes
4answers
156 views

Linking Domain Names to Port Numbers

I have a [game] server (CentOS) that has about 10 used ports. For one game in particular, I have 2 servers: a private one and a public one. The IP for them is the same, so to differentuate between ...
3
votes
6answers
1k views

Finding all domain names that resolve to the same ip?

Lately I've been tracking a spammer on craigslist. I recently discovered that he's added a new technique to his arsenal, he registered a whole bunch of domain names but they all resolve to the same ip ...
2
votes
1answer
1k views

Under what circumstances will Linux ignore the route table when choosing the MAC address for an outbound frame?

While debugging a problem with the networking configuration for a set of virtual machines running under KVM, I discovered a circumstance where the kernel in the guest VM has decided to stamp the ...
2
votes
3answers
4k views

getting error “SIOCADDRT: File exists” when trying to restart network on ubuntu

Error/stdout /etc/init.d/networking restart * Reconfiguring network interfaces... SIOCADDRT: File exists Failed to bring up eth0. ...done. netstat -nr Kernel IP routing table Destination ...
0
votes
1answer
2k views

IP Camera working on lan but not on internet

My IP cam model is Genius 350TR, I tested the cam at home on lan and internet and it worked. Then I shifted it to an office. It works on the office lan setup but I cannot connect to the ip cam from ...
0
votes
1answer
192 views

Subdomains. How do you do development with subdomains?

I am currently building an web app which also utilizes websockets. (Rails for webserver and Nodejs for socket.io) I have structured my application to use subdomains to separate between connection to ...
52
votes
6answers
445k views

How to determine the hostname from an IP address in a Windows network?

My LAN has 50 Windows hosts. At the Windows command line I try ping to get the IP address of a running Windows machine. The question is how to get hostname of a specific IP address in the same ...
35
votes
11answers
9k views

Why would you use IPv6 internally?

Of course, I realize the need to go to IPv6 out on the open Internet since we are running out of addresses, but I really don't understand why there is any need to use it on an internal network. I have ...
21
votes
6answers
10k views

Is it possible for two hostnames share the same IP address?

Can anyone explain whether it is possible for two hostnames to share the same IP address? And what about if one hostname represents more than one IP address, is that possible too? Why?
6
votes
3answers
6k views

How can I do traffic shaping in Linux by IP?

We have a transparent proxy setup. I tried looking for traffic shaping in Linux, and all I could find online was to limit traffic by interface (eth0/eth1...). I need to limit the bandwidth (never ...
10
votes
1answer
261 views

Under what circumstances is TCP-over-TCP performing significantly worse than TCP alone (2014)?

Many admins keep perpetuating - on ServerFault and elsewhere - how bad of an idea TCP-over-TCP is, e.g. in VPNs. That even the slightest packet loss will make one suffer from at least severe ...
13
votes
4answers
15k views

How is route automatic metric calculated on Windows 7?

KB299540 explains how Windows XP automatically assign metrics to IP routes: The following table outlines the criteria that is used to assign metrics for routes that are bound to network interfaces ...
8
votes
2answers
3k views

How can I send visitors to the closest server using DNS?

Is there a way to localize dns entries? Meaning, that users from asia resolve mydomain.com to another ip than users from usa or europe. This would be helpful to give the users the server nearby. DNS ...
7
votes
7answers
16k views

Is it possible to match an internal IP address to a switch port?

I'm trying to find a computer that has a certain IP address on our internal network. I have identified the computer name from DNS, but in this case it does not help me. Just wondering if I can ...
2
votes
3answers
2k views

A tool to change the default bind interface for a given command?

This is somehow related to Change interface for doing a whois The differece is that I'd like to know if it's possible to specify the default interface only for a specific program - not system-wide. ...
33
votes
5answers
3k views

Is it valid to have part of an IPv4 address set to zero?

I am working on a change in a Java EE application that would authenticate based on the user's IP address using ServletRequest.getRemoteAddr. We store IP address ranges (FROM_IP and TO_IP) in a ...
9
votes
3answers
744 views

Creative IP/subnet/dns schemes

I've only administered rather small networks (<=25 nodes). Usually I put the gateway .1, dns/proxy as .10, mail at .20, printers at .30-39 and so on and so forth. I never directly use IP addresses ...
3
votes
1answer
5k views

Keepalived for more than 20 virtual addresses

I have set up keepalived on two Debian machines for high availability, but I've run into the maximum number of virtual IP's I can assign to my vrrp_instance. How would I go about configuring and ...
10
votes
3answers
2k views

How are IP addresses actually assigned?

I'm having a hard time understanding how a governing body assigns IP addresses, companies use BGP to advertise those IPs, and how the internet works. Then, where the hell does DNS come in? Can ...
7
votes
4answers
886 views

CIDR Ranges for Everything except RFC1918

I'm looking for a list of CIDR blocks for "The Internet", i.e. everything from 0.0.0.0 to 223.255.255.255, excluding RFC1918 address space of 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 (yes, I know ...
7
votes
3answers
4k views

Is there an “official” name to the 0.0.0.0 IP address?

As 127.0.0.1 is known as the loopback address, is there a shorter term to refer to 0.0.0.0 other than "the IP address who means all IP address on local machine"?