Definition

static IP address

A static IP address is a 32 bit number that is assigned to a computer to be its address on the internet. This number is in the form of a dotted quad and is typically provided by an internet service provider (ISP).

First, an IP address (internet protocol address) acts as a unique identifier for a device that connects to the internet. Computers use IP addresses to locate and talk to each other on the internet, much the same way people use phone numbers to locate and talk to one another on the telephone. An IP address can provide information such as the hosting provider and geographic location data.

As an example, when a user wants to visit WhatIs.com, their computer asks a domain name system (DNS) server -- analogous to a telephone information operator -- for the correct dotted quad number. The DNS maps the domain name to the IP address, which is needed to identify a device with a network protocol. In this case, the DNS server will link the quad number -- analogous to a phone number -- for WhatIs.com, and your computer uses the answer it receives to connect to the WhatIs.com server.

When an individual signs up with an ISP, they are provided with either a static or dynamic IP address. Most use cases will now see people using dynamic IP addresses over static IP addresses -- especially in home use; however, the use of a static IP address still may have some advantages in select business-centric use cases.

Static vs. dynamic IP address

The main difference between static and dynamic IP addresses is in the terminology of static and dynamic. In a literary sense, the term static character means a character that stays the same throughout a story, and the term dynamic character refers to a character that changes throughout a story. Static and dynamic IP addresses follow the same pattern -- as static refers to unchanging, and dynamic refers to changing. This means that the numbers associated with a static IP address do not change, while the numbers associated with a dynamic IP address do change.

Normally, a dynamic IP address can stay the same for days, weeks or longer, but can also be changed by the ISP or through a reset of the router or modem as well. The address change does not affect the end user either. The address can even change while the user is on the web. In most cases, in home use for example, when an ISP assigns a device an IP address, it will be a dynamic IP address.

A static IP address does not change and, in most cases, will cost an additional fee through the ISP. Static IP addresses have to be reserved from a limited number of IP addresses. Static IP addresses will stay the same no matter what the user does unless they request their ISP to change it. Businesses might want to use a static IP address to ease operations.

In most cases, however, a static IP address is the cheaper, better option.

Advantages

Even though dynamic IP addresses are used more often, both have advantages found in either their functionality or implementation.

Dynamic IP addresses host benefits such as the following:

  • They require less maintenance compared to a Static IP address -- making it ideal for home use, where users might not have a lot of technical knowledge.
  • Network configuration is done automatically -- meaning that users don't have to worry about configuring their IP address.
  • Dynamic IPs are more economical, considering there are a limited number of static IPs.
  • They are more cost-effective compared to static IPs.
  • And dynamic IPs lower security risks, as a device is assigned a new IP address each time a user logs on.

Because they aren't used as often, it may be difficult to see where static IP addresses still have advantages. However, a static IP address has advantages such as the following:

  • Businesses that rely on IP addresses for mail, FTP and web servers can have one, unchanging address.
  • Static IP addresses are preferred for hosting voice over IP, virtual private networks (VPNs) and games.
  • They can be more stable in the case of an interruption in connectivity -- meaning packet exchanges won't be lost.
  • They allow for file servers to have faster file uploads and downloads.
  • A static IP will make it easier for any geolocation services to access where a device is.
  • Static IPs are better for remote access to a computer.
  • A static IP address-enabled device does not need the device to send renewal requests.
  • Static IP addresses can be simpler for network administrators to maintain considering running servers.
  • And it is easier for administrators to track internet traffic, assigning access to users based on IP address.

Disadvantages

Although dynamic IP addresses are more commonly used, they still have some disadvantages that users should be aware:

  • Possible network failure has the potential to cause extended downtimes -- for example, if a Dynamic Host Configuration Protocol (DHCP) server fails.
  • Security issues exist around DHCP automation. If control over a DHCP server is lost, then users who connect to it could be intercepted and their information could be accessed.
  • Dynamic IPs are less reliable for tasks such as voice over IP, VPNs or playing games online, as the service could disconnect.
  • Geolocation services will have a rougher time in finding the accurate location of a device.
  • Businesses with dynamic IP addresses may prefer employees to work on-site to ensure secure access to their network's servers.
  • Dynamic addresses will need a program to assign and change IP addresses.

On the other hand, a static IP address has disadvantages as well:

  • It limits the amount of IP addresses. A static IP address assigned to a device or website is occupied until otherwise noted, even when the device is off and not in use.
  • Most people do not need a static IP address now.
  • Because the IP address is constant and cannot easily be changed, a static IP address is more susceptible to hackers or follow-up attacks.
  • It can be complicated to set up a static IP manually.
  • It may be difficult to transfer server settings from a static IP device to a new one if the original device becomes obsolete.
  • Devices with a static IP are easier to track.
  • Static IPs are more costly, as an ISP will typically need static IP users to sign up for a commercial account and pay one-time fees. Monthly internet service costs may go up as well.
  • Security concerns with both static and dynamic IP addresses can be addressed by implementing router firewalls, using a VPN or by using an internet security suite. Although these don't absolutely guarantee security, they can help significantly.

When an static IP address is necessary

Since dynamic IP addresses are used most commonly now, it is important to note when using a static IP address is necessary. Businesses will mostly use static IP addresses if they are hosting servers and websites which require a high uptime percentage, use voice over IP or have employees that work from home often. If employees want to remotely access their device from home, a dynamic IP address would require the employee to know the new address. Using a remote access application and a static IP address, an employee can always access their computer with that same address.

In most cases, static IP addresses will be used by businesses to ease operations with FTP; email; and VPN servers, database servers, network equipment as well as with web hosting services. In these cases, businesses that will handle a lot of data in these areas will find having a static IP address useful for employees and customers alike that have to connect to the organization's servers.

Using an IP address that changes can be difficult for hosting a website since with each new IP address, the router settings would have to change in order to forward requests to the right IP address. Without that process, no end user could reach the website since the router wouldn't know what device in the network is hosting the website.

DNS servers will also typically use static IP addresses. If the IP address changed regularly, then the DNS server would have to be reconfigured on a router just as often.

When a device's domain is not accessible, then a computer can still connect to a server in the network using a static IP address. As an example, a computer could always be set to connect to a server's static IP address instead of its hostname. This would mean that a computer could still connect to a DNS server, even if the DNS server isn't functioning correctly.

Essentially, any service or feature that requires a constant connection should have a static IP address. Even though it may feel seamless for the end user, when dynamic IP addresses are assigned a new number, any previously connected user is removed from the connection and must then wait to find the new address and reconnect. This is why services that require a consistent connection, such as a file-system service or online game will use a static IP address.

If needed, a LAN administrator can use a DHCP to assign IP addresses that don't change. This can be very useful when a specific user needs to keep their IP address in a situation such as in a firewall rule, where only that IP address is allowed to access a certain site. Another example could be when a scientific journal is published on the internet while using the source IP address of the user for licensing. In this case, users must always have the same IP address.

An organization should nearly always use a dynamic IP address in almost all situations except for the ones listed above, as dynamic IP addresses are the more cost-effective method.

Steps to obtain a static address

To obtain a static IP address, first, an individual will need to pick the device they want to assign the static IP address to, and then they will need to find the MAC address on the chosen device. On a router, the MAC address can normally be found on a sticker on its bottom. If unsure on what the MAC address is, the individual's ISP should be able to provide the information. The MAC address may also be labeled as a physical address. From this point, the individual should contact their ISP and ask to purchase a static IP address. The ISP should then ask for the device's MAC address. From this point, it will likely take a couple of days for the ISP to assign the device with a static IP address, but once the device is assigned a new, unchanging IP address, the user will need to reset their device at least once.

To view what one's IP address is in Windows operating systems such as Windows 10, 8 or 7, one should open up the Control Panel from the Start menu, open either the Network Sharing Center or Network and Internet option, then select Network and Sharing Center. The user should then select the Change Adapter Settings option, right-click on Wi-Fi and select the Properties option. The user should click the Internet Protocol Version 4 (TCP/IPv4) option, followed by Properties, and use the following IP address. The user should be able to see the IP address, Subnet mask, default gateway and DNS server and make changes to those options. After selecting OK, the IP address should be displayed.

Security

On a base level, dynamic IP addresses generally have better security because they change with each session or login. This makes it more difficult for an individual, such as a hacker, to track and compromise an individual's data, such as their geolocation. A hacker will have a rougher time targeting networked equipment on a dynamic IP address. Because static IP addresses don't change, data may be easier to locate and to gain access to; the static IP addresses' unchanging nature also leaves them more likely to be hit by follow-up attacks. Static IP addresses are also easier to track.

However, security concerns are not just left to static IP addresses, as dynamic IP addresses also have security concerns. Namely, there are security issues around DHCP automation concerning dynamic IP addresses. If the control over a DHCP server is lost, then users who connect to it could be intercepted, and their information could be accessed. Businesses with dynamic IP addresses may prefer employees work on-site to ensure secure access to their network's servers. Employees might also have a harder time connecting to a dynamic IP address from remote access controls, which may discourage them from working off-site.

However, security deficiencies found in static and dynamic IP addresses can help be mitigated by implementing a router firewall, security suite or VPN. A VPN, for example, can help in obscuring your network address, making it more difficult to find a device's physical location. Although these measures don't guarantee that all data will be safe at all times, they can help by a large margin, making it a good idea to implement additive security processes.

IPv6

IPv6, which has also been called IPng (IP Next Generation), lengthens IP addresses from 32 bits to 128 bits (16 bytes) and increases the number of available IP addresses significantly, making static IP addresses easier and less expensive to obtain and maintain. A large portion of internet traffic still uses IPv4 today, but more internet traffic is shifting to the use of IPv6 -- meaning both are in use today. Both static and dynamic IP addresses will use IPv4 and IPv6. IPv4 was first deployed in the early 1980s, with only small revisions since then.

The Internet Engineering Task Force (IETF) originally came up with the IPv6 standard and officially passed it as a standard in 2017. IPv6 allows for up to 340 undecillion unique IP addresses. For reference, that is 340 followed by a total of 36 zeros, or, in other words, 340 trillion, trillion, trillion unique IP addresses that can now be assigned. This extension to the total amount of IP addresses allows for considerable future growth of the internet and provides relief for what was perceived as a future shortage of network addresses.

IPv6 supports auto-configuration, which aids in correcting most of the shortcomings in that were in version 4. IPv6 has also integrated security and mobility features. It supports a 1,280 byte packet size without fragmentation, and does not require DHCP or a manual configuration. IPv6 also uses AAAA host address resource record in DNS, which maps host names to IPv6 addresses; a pointer resource record in the IP6.ARPA DNS domain, which maps IPv6 addresses to host names; and a Flow Label field, which identifies packet flow for quality of service (QoS) handling by router.

In terms of messages, IPv6 uses Multicast Neighbor Solicitation messages to resolve IP addresses to link-layer addresses; Multicast Listener Discovery (MLD) messages, which manage membership in local Subnets; and Internet Control Message Protocol version 6 (ICMPv6), which handles Router Solicitation and Router Advertisement messages and determines the best default gateway from the IP address.

IPv6, however, does not include a checksum in the header, meaning that a packet may be delivered incorrectly if there are any transmission errors. It is also important to note that IPv4 and IPv6 devices cannot communicate directly to each other, and that understanding IPv6 Subnetting can be difficult.

IPv6 is seen to be an inevitable need, but still has a slow adoption rate due to cost and the complicated process of moving to IPv6 from IPv4. ISP's may sometimes offer support for both versions of IP addresses.

How dynamic IP addresses work

It would be simple if every computer that connects to the internet could have its own static IP number, but when the internet was first conceived, the architects didn't foresee the need for an unlimited number of IP addresses. Consequently, there were not enough IP numbers to go around, at least until the later advent of IPv6. To get around that problem, many internet service providers limit the number of static IP addresses they allocate and economize on the remaining amount of IP addresses they possess by temporarily assigning an IP address to a requesting DHCP computer from a pool of IP addresses. The temporary IP address is called a dynamic IP address.

Requesting DHCP computers receive a dynamic IP address (analogous to a temporary phone number) for the duration of that internet session or for some other specified amount of time. Once the user disconnects from the internet, their dynamic IP address goes back into the IP address pool so it can be assigned to another user. Even if the user reconnects immediately, odds are they will not be assigned the same IP address from the pool. Keeping the telephone analogy going, using a dynamic IP address is similar to using a payphone. Unless there is a reason to receive a call, the user does not care what number he or she is calling from.

There are times, however, when users who connect to the internet using dynamic IP wish to allow other computers to locate them. Perhaps they want to use CU-SeeMe or use a voice over IP (VoIP) application to make long-distance phone calls using their IP connection. In that case, they would need a static IP address. The user has two choices; they can contact their ISP and request a static IP address, or they can use a dynamic DNS service. Either choice would likely involve an additional monthly fee.

Using a dynamic DNS service works as if there was an old-fashioned telephone message service at one's computer's disposal. When a user registers with a DNS service and connects to the internet with a dynamic IP address, the user's computer contacts the DNS service and lets them know what IP address it has been assigned from the pool; the service works with the DNS server to forward the correct address to the requesting DHCP computer -- similar to calling the message service and saying "Hi. I can be reached at 435.44.32.111 right now. Please tell anyone who tries to reach me to call that number." Using a dynamic DNS service to arrange for computers to find you even though you are using a dynamic IP address is the next best thing to having a static IP.

This was last updated in October 2019

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