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

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How reliable are IP address-based firewall restrictions?

On some of my production systems that need to be accessible outside of the LAN I will sometimes add a firewall restriction at the edge to only permit traffic on, say, RDP from a specific origin IP ...
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IP changed when EC2 instance stopped and started

I have a strange issue here regarding and EC2 instance. I had just stopped and started an EC2 instance for windows after expanding the boot drive, not after I had started the instance, the IP it was ...
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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.
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How secure is limiting site access by IP? [closed]

I'm currently developing software which requires various remote sites to securely connect to our servers to access a basic webapp. Up until now, I've been working on a client/server VPN setup - it's ...
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ip address scope parameter

In Linux, the command ip address add [...] has a scope argument. The man page says that the scope is "the scope of the area where this address is valid". Follows the list of legal scopes: global ...
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How to prevent/firewall calls to AWS EC2 Instance Metadata API?

The AWS EC2 Instance Metadata API provides a lot of useful functionality. Anyone on the actual EC2 instance can make a call to http://169.254.169.254/ and see metadata for the instance the call was ...
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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 - ...
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/etc/interfaces file for multiple gateways, same network? (linux)

I've got my ip routing table setup as I'd like it: # ip r s 10.1.248.0/24 dev eth0 proto kernel scope link src 10.1.248.11 default via 10.1.248.1 dev eth0 metric 100 default via 10.1.248.3 dev ...
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“cat /proc/net/dev” and “ip -s link” show different statistics. Which one is lying?

I notice that /proc/net/dev says eth3 has 1753 drops. ip -s link shows 0 dropped. Why is there a difference? Where is the different data coming from? Which one is correct? I've stripped the out extra ...
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Can I buy an IP address range without buying from or becoming a member of my regional NIC?

My company has been investigating the possibility of buying our own IP ranges as we're growing at a very fast rate. However, the cost of doing business directly with our local NIC is proving to be ...
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Ubuntu 12 crashed and took down network

We recently set up a new Ubuntu 12.04LTS server on our network. It's not fully configured so it's not doing much beyond sshd and a default apache2 install. But this evening it appears to have ...
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Redirection by IP causing infinite loop

I am working to transfer a server from one box to another and do a massive code update tonight. To do this I'd like to set up a redirection so that normal site visitors go to a holding page. But ...
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POST of MTU + ~798 bytes gets lost

I have a very weird issue with certain packets not arriving on the destination host. It happens when we transmit a POST that is somewhat larger than the MTU. We can reproduce it with this script: ...
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Openvpn, forward packets very slowly

I rebooted my server, and an odd issue just came out. I am running on ArchLinux, the clients are Ubuntu, Android and Mac. The problem is that accessing the internet via the clients is slow, about ...
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In Active Directory, what is the relation between IP, MAC, and OS?

I have one machine on which I want to run 2 different OSs, dual boot between Windows Server 2008R2 and 2012R2 (or others). I want to keep the same computer name, the same IP address, and the same MAC ...
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Is it possible to find the actual source IP of a packet with a spoofed IP header?

I recently came under a DDoS attack. It was a SYN flood using spoofed IPs. Is it at all possible to trace the attack back to the actual sending server?
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How do you keep track of which IP addresses are used on your network?

What tools are available for allocating and tracking which addresses are being used? Specifically, our issue is that sometimes an IP is taken for a VM and when we go to build new ones they're not ...
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What does ::1 mean?

What does ::1 mean? I'm trying to find out my IP and the result is ::1.
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Best way to use large IP blacklist to deny access to a web server?

Is there efficient and easy way to use IP blacklist (like this one, but perhaps 2-3 times larger, which can't be simplified to CIDRs much) to deny access to a web server (either lighttpd or Apache) ...
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Another domain name pointing to my server IP?

I was checking out my reverse-DNS entry of my domain the other day which is run from a dedicated server. I noticed that another person/company had their domain pointing to my server? I have no idea ...
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How to work out how many IP's you've got available on a /29 network mask

This might sound like a stupid question but I would really like to know how I would work out how many IP's I've got available on this network range: 196.44.198.32/29 Can someone explain it to me, ...
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hosting IP change, how much downtime to expect?

i'm moving my hosted site (same host) to a static IP, I understand there will be some downtime due to DNS caching - does anybody have any tips how to minimize this time and to avoid my users seeing ...
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Can you use IP V6 for name server records

This might sound like a stupid question as I have a very basic grasp of DNS management, but I'm looking for a new VPS and most providers only offer one IPV4 address, which doesn't validate on ...
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Finding ALL currently used IP addresses of Website [closed]

What steps would you take to discover all (or close to all) IP addresses that are currently used by a website? How would you be as exhaustive as possible without calling a website admin and asking ...
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Are there simpler ways to do traffic shaping in linux besides tc?

I read lartc but I don't feel I need such a complicated solution for simple needs. One of such simple use cases is to limit a specific process' available bandwidth, upstream or downstream. How can I ...
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Share one IP address with a simple router

We have just moved into a new office and have been given our 'internet connection' in the following form: One Ethernet cable in the corner of the room An IP address with subnet mask 255.255.255.0 ...
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How do I get my server off the ivmSIP/24 blacklist?

I checked my server IP using this tool: http://www.mxtoolbox.com/SuperTool.aspx It's come up on the ivmSIP/24 list. What can I do to get my IP removed from this list? I have SPF records set to ...
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Remote desktop into multiple different workstations sharing a single DSL line

I have been asked to help setup a remote desktop solution for a small business that has about 10 workstations. All 10 workstations are sharing a single verizon dsl line with (presumably) a low-end ...
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Subnet Mask problem

I'm studying for a test and found myself in a "dead end" with a question about netmasks. The question is: Based on the next figure, once both sub-nets are configured, it's observed that hosts in a ...
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What does 192.168/16 mean? [closed]

OK, this isn't really a server question in practice, but I'm pretty sure it has something to do with server management. What is this joke supposed to mean?: http://xkcd.com/742
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What does ifconfig promisc mode do, or promiscuous mode in general?

This is what man ifconfig has to say about it. [-]promisc Enable or disable the promiscuous mode of the interface. If selected, all packets on the network will be received by the ...
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How to get the IP Address for your Local Area Connection on Windows Server?

I want to create a batch or vbs file that will put together a url and executed. Part of that url needs to be the actual ip address of the machine. How I am able to get that IP address in a variable ...
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Redirecting to the IP of an amazon EC2 instance

As you know amazon EC2 instances get an address like: ec2-72-44-40-153.z-2.compute-1.amazonaws.com If I have the domain example.com, is there any way that I can make bob.example.com or preferably ...
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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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IP address range for examples in documentations

Is there an IP address range dedicated to example in documentations ? (Like example.com for DNS)
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Access server via IP v6?

Question: I'm playing with IPv6 and converting it to IPv4 and vice-versa. I wanted to access http://127.0.0.1/ And did the standard ipv4 to ipv6 calculation: AA = 127 BB = 0 CC = 0 DD = 1 with the ...
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What can I do with an IP address of a visitor that tried to access a shell exploit that was planted on my system?

My website was exploited (don't worry about how) and the result was there were several WebShells installed in various locations. The exact web shell is just like the one listed in this question here ...
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Monitor network traffic volume over interface

Is there a way to monitor the traffic (e.g., get a live view of the utilization) over a particular network interface, say eth0? The catch here is that the set of tools on the box is fixed, and is ...
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Is IP over FC still crazy complex? [closed]

In the link below, it is explained that 4 years ago IP over FC was crazy complex: How do I set up IP over FC? Is that still the case on CentOS 6?
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Remove IP with ip command in linux

If I add two IPs like this: ip addr add 1.1.1.1/24 dev eth2 ip addr add 1.1.1.2/24 dev eth2 and then I try to delete one of like this: ip addr del 1.1.1.2/24 dev eth2 BOTH IPs will be deleted ...
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DNS Issue - Windows 2003 environment

Odd issue and I'm not having much luck with ole google (perhaps I'm not looking in the right direction). Hoping to get a little help with that here from some of you. On our network we have approx. ...
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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 ...
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How to Deny all IPs except one in Filezilla Server?

Using the standard Filezilla IP Filter GUI interface seen here, I want to deny all IP addresses in the first box and in the second box allow only one IP# back in. Am having problems with CIDR ...
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max number virtual IP addresses per NIC

How many virtual IP addresses are allowed to be added per network card? I am running a Linux OS.
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Resolving IP address conflicts on a LAN

We have our LAN set up with DHCPD providing fixed IP addresses to the systems. However we are facing IP address conflicts if some one connects a laptop and assigns an IP address belonging to another ...
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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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Configuring several IPs on centOS from different networks

So i have a plesk centos server. This server has public IPs and is hosted at a datacenter. And i have several IPs. The ones working lets say 192.168.1.50 .51 .52 192.168.1.50 is configured has eth0 ...
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Server with dynamic ip?

I was wondering if it was possible to have a redirect to a server that is under dynamic ip. I'm using www.no-ip.com to redirect to my dynamic ip. Since my ip changes everyday, I have to manually ...
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How do I block an IP address or network block with Varnish VCL?

How does one block either IP address of network range inside of Varnish's VCL file?
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How do I configure a subdomain to point to a different IP from GoDaddy

Simailar to this question, I want to configure DNS hosted with GoDaddy to have a subdomain on a different IP from the root site. The issue I am having is that GoDaddy uses a GUI and does not grant ...