Montenegro is a country in Southeastern Europe. It is located on the Adriatic Sea and is a part of the Balkans, sharing borders with Serbia to the northeast, Bosnia and Herzegovina to the north and west, Kosovo to the east, Albania to the southeast, and the Adriatic Sea and Croatia to the southwest. Podgorica, the capital and largest city, covers 10.4% of Montenegro's territory of 13,812 square kilometres (5,333 sq mi), and is home to roughly 30% of its total population of 621,000.
A top-level domain (TLD) is one of the domains at the highest level in the hierarchical Domain Name System of the Internet after the root domain. The top-level domain names are installed in the root zone of the name space. For all domains in lower levels, it is the last part of the domain name, that is, the last non empty label of a fully qualified domain name. For example, in the domain name www.example.com., the top-level domain is com. Responsibility for management of most top-level domains is delegated to specific organizations by the Internet Governance Forum (IGF) an Internet multi-stakeholder community, which operates the Internet Assigned Numbers Authority (IANA), and is in charge of maintaining the DNS root zone.
ISO 3166-3 is part of the ISO 3166 standard published by the International Organization for Standardization (ISO), and defines codes for country names which have been deleted from ISO 3166-1 since its first publication in 1974. The official name of the standard is Codes for the representation of names of countries and their subdivisions – Part 3: Code for formerly used names of countries. It was first published in 1999.
.cd is the Internet country code top-level domain (ccTLD) for the Democratic Republic of the Congo. It was created in 1997 as a replacement for the .zr (Zaire) ccTLD, which was phased out and eventually deleted in 2001.
ISO 3166-2:CS was the entry for Serbia and Montenegro in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
.uk is the Internet country code top-level domain (ccTLD) for the United Kingdom. It was first registered in July 1985, seven months after the original generic top-level domains such as .com and the first country code after .us.
A country code top-level domain (ccTLD) is an Internet top-level domain generally used or reserved for a country, sovereign state, or dependent territory identified with a country code. All ASCII ccTLD identifiers are two letters long, and all two-letter top-level domains are ccTLDs.
.sk is the Internet country code top-level domain (ccTLD) for Slovakia. It is administered by SK-NIC a.s.
.su is an Internet country code top-level domain (ccTLD) that was designated for the Soviet Union (USSR) on 19 September 1990. Even though the Soviet Union itself was dissolved a mere 15 months later, the .su top-level domain remains in use today with over 100,000 .su domains as of July 2020. It is administered by the Russian Institute for Public Networks.
.yu was the Internet country code top-level domain (ccTLD) that was assigned to SFR Yugoslavia in 1989 and was mainly used by the Federal Republic of Yugoslavia and its successor states after 1994. After Serbia and Montenegro acquired separate .rs and .me domains in 2007, a transition period started, and the .yu domain finally expired in 2010.
.il is the Internet country code top-level domain (ccTLD) of Israel. It is administered by the Israel Internet Association and managed by NIC - ISRAEL, which hosts the DNS root server and manages the Israeli Internet Exchange, that supports IPv4 and IPv6.
.cz is the country code top-level domain (ccTLD) for the Czech Republic. It is administered by CZ.NIC. Registrations must be ordered via accredited domain name registrars.
In the Domain Name System (DNS) hierarchy, a second-level domain is a domain that is directly below a top-level domain (TLD). For example, in example.com, example is the second-level domain of the .com TLD.
A domain hack is a domain name that suggests a word, phrase, or name when concatenating two or more adjacent levels of that domain. For example, "bir.ds" and "examp.le", using the fictitious country-code domains .ds and .le, suggest the words birds and example respectively. In this context, the word hack denotes a clever trick, not an exploit or break-in.
.rs is the Internet country code top-level domain (ccTLD) for Serbia. The domain name registry that operates it is the Serbian National Internet Domain Registry (RNIDS). The letters rs stand for Republika Srbija/Република Србија.
.me is the Internet country code top-level domain (ccTLD) for Montenegro.
The Internet in Serbia is well developed. The Internet country code top-level domain (ccTLD) for Serbia is .rs and .срб. (Cyrillic)
.срб is the Internationalised (Cyrillic) Internet country code top-level domain for Serbia. It has been active since May 3, 2011.
Country code top-level domains with commercial licenses are Internet country code top-level domain that have adopted a policy for worldwide commercial use.
As the state union of Serbia and Montenegro dissolved following the independence referendum in Montenegro, newly independent Serbia dealt with the issue of assignment of country codes. This task, which could seem trivial, is made hugely complex by the number of countries in the world having names which begin with the letter S. In September 2006, the proposal of the Serbian government to obtain the code RS was accepted by ISO.
Czechoslovakia (originally, until deleted) and later 
Serbia and Montenegro (reserved, but never used)