CenturyLink Data Services - Frequently Asked Questions
IP Addresses & BGP
What is an IP address?
An IP address is a 32-bit number that identifies each sender or receiver of information that is sent in packets across the Internet. The IP address allows the Internet to locate your Internet connected device. This provides you the ability to send and receive e-mail, surf the web, download files and many other tasks.
Thank you for asking, since IP numbers are being rapidly exhausted, it is more difficult to obtain IP addresses from the American Registry for Internet Numbers (ARIN). ARIN now requires extensive documentation for new IP address allocations. Only with valid justification can anyone obtain a partial, full or multiple Class C networks. Fortunately, the need for more IP numbers can be avoided, if you are simply providing web hosting services. In addition there are several technologies which allow you to conserve IP address space for WAN (Wide Area Networks) and LAN (Local Area Networks) as well. Please see the resources provided below. You can also find additional information using your favorite search engine and entering in the appropriate topic.
How can I plan my network to use less IP addresses?
|Address Allocation for Private Internets
|Configuring Network Address Translation HTML or PDF
|Virtual Web Hosting
Virtual web hosting let's you assign any number of Virtual Hosts to the same IP number. You can have www.domain1.com and www.domain2.com both use the same IP number without changing how each site is reached through the Internet.
IP Addressing and subnetting HTML or PDF
How do I subnet the network CenturyLink provided me?
How do I request IP address space from CenturyLink?CenturyLink will provide IP address space to downstream, directly connected Internet customers. In accordance with the guidelines set forth from The American Registry of Internet Numbers (ARIN), CenturyLink will issue the smallest network which will provide you with the appropriate number of IP addresses to build your network. Currently the default assignment is a /29 network (6 usable IP addresses).
Because the number of available IP addresses on the Internet is limited, many factors must be considered in the determination of address space allocations. Therefore, IP address space is allocated to downstream customers using a slow-start model. Allocations are based on justified need, not solely on a predicted customer base.
If you require address space longer than a /20 (16 Class C Networks) or more, you should request your networks directly from ARIN.
In requesting the IP address space you must provide CenturyLink sufficient justification in the form of detailed documentation of network plans, and justification for use of all IP addresses, including previously assigned networks.
Customers must complete a IP Request Form. There are documents for ISPs (Organizations who provide IP services for other individuals or companies) and End Users (Organizations who only provide in house IP services).
IP requests will be processed within 96 business hours of receipt. This time many vary due to number of other IP requests received in addition to receiving sufficient justification and utilization documentation. If you need assistance in completing the CenturyLink Regional Dedicated IP form please call our IP services support team at 1.800.603.8044 Options 1,2.
CenturyLink will submit the proper Shared WhoIs Project (SWIP) documentation based on information provided by the IP Services subscriber, their sales representative or other entity representing said IP services subscriber. Once a SWIP registration is submitted the ORG ID becomes the responsibility of the IP Services subscriber for whom it was submitted. SWIP submissions can be viewed in ARIN's WhoIs database.
BGP (Border Gateway Protocol) is the current Internet standard for interdomain AS (Autonomous System) exterior routing. BGP4 allows traffic to use the best path available at the time of transmitting and receiving data. The current version in use is BGP4, which is based on RFC 1771, it provides intelligent route based selection on the most specific prefix and shortest AS path. BGP4 supports Classless Interdomain routing.
What is BGP?
How do I request BGP peering with CenturyLink's Internet access routers?
BGP can be set up for your connection if you are dual homed to CenturyLink, or multi-homed to another provider. The information below is provided for you to evaluate your options in setting up your BGP session.
||You must be multi-homed to run BGP with at least a full T1 of bandwidth to both providers.
||You must have an (Autonomous System) AS number from ARIN. ASN Request template.
||You must have a class C network to announce, unless you run private BGP peering with CenturyLink.
||You must be capable of configuring your BGP session. CenturyLink can provide BGP configuration at a time and material rate. Please contact your sales representative for pricing.
||The customer will NOT allow unfiltered redistribution from interior routing into the BGP session.
||Explicit distribute-list, or network statements should be used to prevent injections of invalid routes into global tables.
||NO redistribution of BGP routes can be allowed into customer's interior routing protocols, as it corrupts AS-path information.
||The customer has to establish as-path filters, which will aid in preventing leakage of routing information from our customer's alternate Internet access provider to CenturyLink and vice versa. Filters should be inclusive, rather than exclusive (i.e. they should list customer AS-es instead of excluding other provider's AS-es).
||IP blocks for several specific routes should be aggregated into larger routes as much as possible.
||Networks listed in the BGP configuration should be sane (i.e. no networks assigned to other customers, subnets should never be announced outside, etc).
||CenturyLink will not run EBGP Multi-hop except for load balancing purposes between the loopback addresses of the Customer and CenturyLink routers that share multiple serial connections.
||CenturyLink reserves the right to aggregate any announcement for a network smaller than /19 when advertising to external peers such as AT&T, UUnet etc.
||Customers will not be permitted to use '*' wildcards in their requested route filters.
WHAT TO EXPECT
CONVERSION FROM STATIC ROUTING
To change from static routing to BGP, complete and submit a BGP Routing Request Form. Upon successful submission you will receive a confirmation ticket number and a copy sent to your contact e-mail address. CenturyLink Engineers will configure the Internet Access router where your circuit terminates. The static routes will not be removed at this time.
Any time a modification need to be made to your BGP session (AS path filter or the IP filter), the BGP Update Request Form should be submitted. Upon successful submission you will receive a confirmation ticket number and a copy sent to your contact e-mail address. CenturyLink will take action on all requests within 3-4 business days of receiving the request.
WHAT YOU CAN CONTROL
If you request an AS based filter, CenturyLink automatically sets the filter to allow you to prepend your AS as much as you like to control the preference of your routes as advertised to the Internet. If you request an IP based filter, you can prepend your network without any special request or special configuration on the CenturyLink side.
You can control the metric that is assigned to your announcements on the BGP session.
You can set up local preferences on your incoming announcements to prefer a provider to a specific location. Filters can be IP or AS-path based filters. Recall, the default value for local-preference is 100 and the information is shared with all your IBGP neighbors.
How can I view my DNS entries on CenturyLink's DNS servers?
At this time you can use NSLOOKUP and query the name server directly.
What is DNS?
DNS is an acronym for "Domain Name Services"; most people misuse the term for Domain Name Server. This is incorrect because one would not say Domain Name Server Server as in DNS Server, one would say Domain Name Services Server. Domain Name Services are the glue that binds the Internet together. Domain Name Services are used to translate domain names such as www.centurylinkservices.net, which is easy for people to remember, into an Internet Protocol (IP) number or address that computers recognize. For example, if someone wants to access Your Customer Support Website at www.centurylinkservices.net, a DNS server would translate the domain name (www.centurylinkservices.net) into the IP address 22.214.171.124. Your computer is then able to send your request to the correct server located either on your local network or out to the Internet if necessary.
Do I need DNS Services?
The Internet uses IP addresses to transport information from one place to another. If you want to get to websites or use e-mail you will need Domain Name Services. You can use CenturyLink's DNS servers for hostname resolution at no additional charge. If you require domain hosting and provide resolution services, Domain Name Services are part of CenturyLink's Value Added Services. Please contact your sales representative for additional information regarding the DNS Hosting Value Added Service.
Can CenturyLink provide DNS services for me?
Yes, CenturyLink provides Domain Name Services as a Value Added Service. CenturyLink can provide authoritative primary and secondary Domain Name Services for your domain(s). If you choose, CenturyLink also provides authoritative secondary DNS service for a primary DNS server you would provide. Please contact your sales representative for additional information regarding the DNS Hosting Value Added Service.
What are the host names and IP addresses of CenturyLink's DNS servers?
What is a domain name?
A domain name is used to identify the location of a website on the Internet. Here are some domain names you might
be familiar with:
microsoft.com - Microsoft Inc.
ucla.edu - University of California Los Angeles
centurylink.com - CenturyLink Corporation
Does CenturyLink register domain names?
At this time CenturyLink does not provide domain name registration services. Please see ICANN's list of accredited companies
that do perform do
main registration services. CenturyLink makes no specific recommendations to use any specific registrar. If you requ
ire assistance in submitting the information for a new registration, a CenturyLink Internet Service technician will
be able to assist you.
How do I register a new domain?
1. First you have to determine the name you wish to register as a domain. It may be your business name, or a
description of your products, services, or company slogan.
CenturyLink could register:<
2. Second you will need the following information for the administrative, billing, and technical contacts.
- Position titles for each contact
- Company address, including city, state, and postal code.
- Contact telephone number
- Fax number (optional)
- E-mail address - Create an alias e-mail address
- DNS server information - Server hostnames and IP addresses
* Using position titles (a.k.a. Role Account) is a suggestion to protect an individuals privacy. It also aids in
management of the domain; when the person holding the postion changes, changes to the domain registration is not nee
ded. The DNS servers can have up to six unique entries if necessary.
3. Third you will need to find a registry where you can register your dom
ain. Many of the registries have affiliate programs, which allow other companies to provide registration services. S
ince the domain registration services are competative, shop around for domain pricing.
What are the components of a domain name?
A domain name consists of two or more words separated by a period. The last word (the far right) is called a "top-
level domain". Here are some common top-level domains and their use:
.COM - Used for commercial entities. It is the most popular top-level domain. Anyone can registe
r a .com domain.
.NET - Originally used for networking organizations such as Internet Service Providers and backb
one providers. Today, anyone can register a .net domain.
.ORG - Designed for miscellaneous organizations, including nonprofit groups. Today, anyone can r
egister a .org domain.
.EDU - Four-year, accredited colleges and universities.
How long can a domain name be and what are the restrictions?
A domain can have a maximum of 67 characters including the extensions (.com, .net, .org, .edu other TLDs have thei
r own requirements.). Valid characters in a domain name are letters, numbers, and dashes. The domain can not start o
r end with a dash, nor can it contain any spaces. No other characters are valid except as listed.
An example of a valid domain is:
How long can a hostname be and what are the restrictions?
A host name is specified in either relative or absolute domain name format. If you specify the absolute domain nam
e, the portion of the name preceding the first . (period) has a maximum length of 63 characters and cannot contain b
lanks. For both formats of the name, the total number of characters cannot exceed 255
nd each entry must be contained on one line. Multiple hostnames (or aliases) can be specified.
Valid hostnames or alias hostnames must contain at least one alphabetic character. If you choose to
specify a host name or alias that begins with an x followed by any hexadecimal digit (0-f ), the host name or alias
must also contain at least one additional letter that cannot be expressed as a hexadecimal digit. The system interp
rets a leading x followed by a hexadecimal digit as the base 16 representation of an address, unless there is at lea
st one character in the host name or alias that is not a hexadecimal digit. Thus, xdeer would be a valid host name,
whereas xdee would not.
I want to register a domain in another country, what are the Country Codes?
Other top-level domains include those for countries (.CA
for Canada, .UK
United Kingdom, .HK
for Hong Kong, and so forth), which are based on the International Standards Organization's 3166 standard
for country abbreviations. <
To the left of the top-level domain is what is called the "second-level domain." In centurylink.com, "centurylink"
represents a second-level domain within the top-level domain of .com. It is also possible to have a domain name in
the form of somename.centurylink.com. In this case the "somename" is called a "host" name also known as a "sub-domai
n". It is not necessary to register a host or sub-domain with a registry before being able to use it. The resolution
of sub-domains are handled by the authoritative DNS server of the second level domain (SLD) name. To register a dom
ain using one of the country codes find the appropriate registry
for that country.
What is a registry?
A registry is an organization such as OpenSRS, Network Solutions, and eNom who register domain names and enter the
m into central computers (root servers), which are accessed by individual DNS servers throughout the Internet. Regis
try companies report name registrations to ICANN a.k.a. the Internet Corporation for Assigned Names and Numbers, who
assumes responsibility for the for the TLDs .com, .net, .org, .edu, .info, .biz and .gov. ICANN accredited companies
like OpenSRS, charge an annual
fee which varies due to the competitive nature of ICANN Accredited Registries and their resellers.
What is a URL?
It stands for Universal Resource Locator. Some people refer to it as a web address (although URL is not limited to
the web). An example of a URL is http://www.centurylink.com. Please note that a URL is a unique identifier. No two
websites can have the same URL. This is the reason why you should register your domain name before someone else does
What if the name I want to use is already taken?
You can choose an alternative domain name, or if you feel that you have a right to that domain name, such as a your companies trademark, y
ou could follow the Uniform Domain-name Resolution dispute Policy (UDRP
) and try to regain the domain name. If the domain does not appear to be in use, you could contact the administrative contact listed in the WhoIs database.
How long should the registration process take?
If the information provided is correct, it should take less than 24 hours You can check any registry WhoIs tool to see whether or not your
domain name has been registered. Once the domain is registered it has to be put into the root servers which occurs twice daily. Within the
next 72 hours your domain will begin to propagate throughout the Internet.
Once a domain is registered, who "owns" the domain name?
The domain name is owned by the organization that is listed in the WhoIs database. You can view this information by searching for the name using our WhoIs tool.
What domain extensions do CenturyLink's DNS servers support?
CenturyLink's DNS servers support all ICANN approved
ccTLD and gTLD extensions. Our name servers do support New.net
Help!, I no longer have access to the e-mail address listed on my domain registration?
Each Domain Registry has a different proccess required to change invalid administrative contact e-mail addresses.
Please visit the website of your domain registrar to search for their admin e-mail contact change form.
Abuse and Network Security
What is Internet Abuse?
There are several types of Internet abuse, which can be placed into 2 main groups which are defined below.
This type of abuse is identified by:
- An attempt to gain unauthorized access to a network node
- A network node is defined as any component of a network, such as a computer, server, router, or switch, among other devices.
- An attempt to prevent normal traffic to flow in or out of a network or network node. a.k.a. a Denial of Service attack - (DOS attack)
- Types of DOS attacks include but are not limited to:
- Ping attacks
- Broadcast storms, TCP, UDP or any other protocol.
- An attempt to infect a network node with a virus, worm, or other harmful payload.
- An attempt to scan a network or network node without authorization or administrative authority.
- A scan is successive pings or probes to ranges of IP ports or IP addresses.
Administrative authority is defined as a known Network Administrator of a network which has initiated a scan or probe of their assigned network to prevent, resolve, or isolate known or potential issues affecting their network. Example: If the Internet team pinged all of the IP addresses assigned to a given customer. CenturyLink maintains authority for all of the IP networks that it provides to downstream customers.
E-mail Abuse - a.k.a. SPAM
E-mail has become a common way of communicating to coworkers, business partners, suppliers, customers, and the list continues. E-mail has virtually no cost to the user, so sending one e-mail seems no different than sending 1000 e-mails. Here is where some people take advantage of the system and send 1000's or millions of e-mails a day. Most of these e-mail are selling a product (UCE), showing you how to make $5000 in an afternoon (MMF), wanting you to join their company and recruit other members and get commissions from your recruits (MLM). When the same message is sent out to a list of 10 or more people this is what is called Bulk e-mail.
- UCE - Unsolicited Commercial E-mail
- UBE - Unsolicited Bulk E-mail
- MLM - Multi-Level Marketing
- MMF - Make Money Fast
Are there laws against Internet Abuse?
Many states have enacted their own laws, which some of them are listed below. At this time the United States Federal Government has not enacted any laws regarding Internet abuse. The site SPAMLAWS Provides a resource for SPAM related legislation pending or made into law. You can find information for the United States, European Union, and other countries.
Where can I find information to help me stop abuse issues?
Network Security Resources: