Questions tagged [ip-address]

IP address is a numerical label assigned to each device participating in a computer network that uses IP for communication.

An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there."

The designers of the Internet Protocol defined an IP address as a 32-bit number1 and this system, known as Internet Protocol Version 4 (IPv4), is still in use today. However, due to the enormous growth of the Internet and the predicted depletion of available addresses, a new addressing system (IPv6), using 128 bits for the address, was developed in 1995,[3] standardized as RFC 2460 in 1998,[4] and its deployment has been ongoing since the mid-2000s.

IP addresses are binary numbers, but they are usually stored in text files and displayed in human-readable notations, such as 172.16.254.1 (for IPv4), and 2001:db8:0:1234:0:567:8:1 (for IPv6).

The Internet Assigned Numbers Authority (IANA) manages the IP address space allocations globally and delegates five regional Internet registries (RIRs) to allocate IP address blocks to local Internet registries (Internet service providers) and other entities.

Source: Wikipedia.

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Making iptables easier to maintain

My network is completely locked down except for a few sites which are whitelisted. This is all done through iptables, which looks something like this: # Allow traffic to google.com iptables -A zone_lan_forward -p tcp -d 1.2.3.0/24 -j ACCEPT iptables…
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How IP addresses are mapped to Autonomous System Numbers?

How are IP addresses mapped to Autonomous System Numbers (ASNs)? Is there a reference database for it? Then how are these Autonomous Systems geographically located?
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Assigning a fixed IP address to a machine in a DHCP network

I want to assign a fixed private IP address to a server so that local computers can always access it. Currently, the DHCP address of the server is something like 192.168.1.66. Should I simply assign the server this same IP as fixed and configure the…
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google.com different IP in different countries. How?

If you ping google.com from different countries you will get replies from local google servers. How does that work? Can a DNS record have multiple A addresses? Could someone point me to the technology they use to do that? Update. OK, so Google's DNS…
HeavyWave
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nginx not serving requests to external IP address

I have nginx running on port 81. I can telnet using telnet 127.0.0.1 81 and everything is fine. But when I try to telnet to my machine from my Mac (an external IP address), I just get this error: telnet: connect to address 109.123.x.x: Connection…
Eamorr
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Are same IP address with different submask unique?

Possible Duplicate: How does Subnetting Work? In a same block of IPv4 addresses, can there be same IPs with different submasks? For example, can I have this: 180.70.65.140/26 180.70.65.140/25 180.70.65.140/24 All the 3 addresses above have the…
xenon
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Can I find the web hosting company from an IP address?

If I have an IP address, is there a way to find the web hosting service that this IP address belongs to? I tried using whois and traceroute but no luck so far. The case is that my friend bought a domain and storage several years ago and he can't…
ufk
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How do you choose your IP addressing?

In the life of a system administrator, always will come a moment when an IP subnet needs to be defined. Be it your small home LAN or the endless company WAN where madness lurks in the depths of unknown routes, IP addresses will always need to be…
Massimo
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Understand IP addresses and location

I risk posing an ill formed question here, but I'll give it a whirl. Does it generally stand to reason that the nearer IP address A is to IP address B numerically, then the nearer IP address A is to IP address B geographically? Whatever your…
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SSL certificate for a public IP address?

I just tried buying a Comodo Positive SSL but it was rejected due to not supporting a public IP address, but instead they only support a domain name. Does anyone know any SSL certificate provider that supports public IP address instead of a domain…
hsym
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Can I use nmap to discover IPs and mac addresses?

When I need to locate the IPs of devices by their mac address on a Windows system, I normally use Advanced IP Scanner (from radmin.com) to scan the network, then I use arp -a to list the mac addresses. Is it possible to use nmap to perform the same…
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Why do people use 172.x.x.x instead of 192.x.x.x

Since I was a kid, I've always installed our home network with the default 192.168.1.x/24, but whenever i log into my university's network, i notice that they use 172.x.x.x, and the same thing goes for most public places I've connected to before.…
Hammi Cloud
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How often do IP blocks get reassigned to different regions?

Title says it all, really. I'm asking because I've got a subscription to MaxMind, and I'd like to know how important it is to stay on top of updates to their geolocation database.
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How do I move static IP address from one ISP to another

We have a linux server pointing to a static IP address from one major ISP. We recently changed that ISP to a new ISP and I am wondering if there is a way we can move the static IP address to work through the new ISP. Is it even possible to move…
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nginx as proxy using a specific source ip

I'm using nginx to serve static file and proxy other requests to some Tomcat instance. The problem is that I don't know how to choose which IP address will nginx use to connect to Tomcat. Each Tomcat instance only accept HTTP connections from…
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