Introduction 
Cities are rapidly undergoing change and transformation, among which we can mention the presence and activity in the virtual space (the second space), parallel to the physical and real space (the first space) of the city. Cities in which activities are being widely carried out in another space (virtual space or the second space). The use of new technologies in the virtual city in urban spaces is increasing day by day. Although most of these technologies have been accepted and praised as a sign of progress in life and a way to make life easier in cities, some people claim that they may witness disruptive changes in life in cities and the city as well. At the same time, not making two spaces in the city, especially cities like Tehran, which has environmental bottlenecks and heavy car traffic, population, and cultural dispersion, causes much damage and lost opportunities. However, there are some disadvantages to joining these spaces that need to be taken into consideration. In this regard, in addition to the fact that it is necessary to develop comprehensive passive defense components and indicators, to prevent the destruction or damage of uses in the physical space and body of the city, a significant part of the activities and flow of social and individual issues and even the relationship between the government and the people (citizens) will be pushed into the second urban space. So, it is necessary to pay attention to the security of this space through passive defense, because of the fact that the city of Tehran, as the driver of the country’s urbanization and the largest center and human settlement, is moving in the direction of intelligentization at a high speed. Therefore, this research seeks to promote the idea that passive defense for the second space or virtual space of this city will also be as important as a passive defense to defend physical space. Therefore, the current research tries to extract and present the key components of passive defense in accordance with the two-space threats of Tehran metropolis and seeks to determine the passive defense components for Tehran metropolis and urban planners and decision-makers. Help to improve security and protect the second space of citizens’ lives in Tehran’s metropolis against various threats by applying the research results in urban development documents, plans, and programs. According to the research problem, the following question is raised; What are the most important key components of passive defense according to two-space threats of the Tehran metropolis?
Materials and Methods
The current research is applied in terms of purpose and descriptive-analytical in terms of method. The statistical society of the research consists of knowledgeable people, experts, and specialists in the field of passive defense. According to the type of research, the sampling method is based on the purposeful sampling method, and 15 people were determined as the sample size (the statistical population is experts, which include people who are related to having done research on the subject or have worked in jobs related to the subject). Excel software was used to summarize and reduce the data. Also, MICMAC software, which is a structural analysis software, was used to analyze the data and extract the required outputs.
Findings
The current research sought to compile the key components of passive defense in accordance with the two-space threats of the Tehran metropolis. Based on the results of the first part of the research findings, between the components of passive defense in accordance with the threats of cyberspace and the second components of Tehran metropolis: cyber security and resilience (var6) (the level of security and resilience of the information element) preventing the theft and exploitation of data and information by the enemy); security of information-based processes (resistance against destruction and manipulation), security of information systems (var7) (system security) information systems (security against data and information destruction); security of information systems (proofing and security against software damage); security of information systems (security and safety) protection against hardware damage); security of computer networks (resistance and protection against software damage); security of computer networks (protection and security) protection against hardware damage; protection for the continuation of virtual space services and prevention of disruption to public order), protection of arteries and virtual infrastructures (var9), leveling and protection of facilities and remote communication infrastructures; leveling and insulation of telecommunication arteries, Support systems (var11) (establishment of support systems and parallelization of computer support systems), blinding enemy information systems (var5) (hiding vital activities and flows and virtual sensitive) in connection with the general and deepening dimension and soft/psychological resilience (var10) (combating the distortion of realities and governance relations in virtual space; Dealing with the division of the people (ethnically) and the gap between the people and the government in the virtual space; Dealing with provocative and riotous factors in the virtual space) related to the political dimension and optimizing and strengthening the media space (var3) (strengthening audio and visual media (radio and television); strengthening the press and electronic media (publications, books, and electronic newspapers); optimization and strengthening of virtual networks and channels) related to the social and cultural dimension, were selected as key factors in the virtual space and the second dimension.
Conclusion
According to the results obtained from the research findings, it is concluded that the number of key factors in the real space is more and the number of influential factors is less, and this indicates that the physical and real space is more flexible and controllable compared to the virtual space is the second because the virtual space has higher influencing factors than the real space which cannot be controlled or it is very difficult to control them and it requires all-around management to divide Tehran metropolis as much as possible.