One view of what Iran thinks about defending itself from attacks with a "passive defense plan" from without from Memri:
Despite confident pronouncements by Iranian leaders that the West will not dare to attack Iran's nuclear facilities, the Iranian regime has, on orders from Supreme Leader Ali Khamenei, been preparing for this eventuality by means of a comprehensive emergency plan called "Passive Defense." Examination of the plan reveals that the regime's main fear is of an attack on Iran's vital infrastructures, which would ultimately lead to its downfall. Therefore, alongside a defense doctrine based on preemptive attack, long-range ballistic missiles, and asymmetric guerilla warfare, it has formulated a doctrine of "passive defense," based mainly on cooperation between regional Passive Defense Councils and the regime's popular militia, the Basij.Mmmm. Infrastructures...
Jalali expressed Iran's concern that the West would attack Iran from the sea and air with the aim of destroying vital infrastructure, ultimately bringing about the downfall of the regime. He said:
"With military bases and forces around [Iran], America has access to the entire territory of the country. The Islamic Republic of Iran is a political regime that relies upon the [Iranian] people... If the enemy aims to change the regime, it can achieve this by disrupting the [regime's ability] to administer the population. To this end, the enemy will attempt to paralyze infrastructures and the vital institutions of the regime, in order to sow dissatisfaction among the people.
"Under these circumstances, the war and the administration of the population are inseparably linked. That is, the enemy will try to destroy the infrastructures [vital to] people's lives, and we must protect the people while providing necessary services. According to some analyses, the  Lebanon war was 'a war of bridges,' because Israel destroyed all bridges in Lebanon, large and small, in order to cut off all land routes. In other words, in that war, the immediate aim was to [destroy] the infrastructures [that permit] administering the population, but the ultimate aim was to render such administration impossible.
"Asked in an interview about the nature of a possible attack on Iran, and [in particular] on Tehran, a U.S. colonel said that... [U.S. forces] would be deployed around the city, would strike its infrastructures from the air, and would, with the help of elements affiliated with [the U.S.], sow dissatisfaction among people. In other words, using these two methods - destruction of infrastructure and psychological warfare - [they] will instigate a popular uprising against the government. To confront this kind of threat, we must employ all [our] defense strategies and abilities. This is asymmetrical warfare, since our military capabilities are not on par with those of the U.S. Hence, if we want to stand up [to the U.S.], we must employ 'passive defense' along with 'active defense' [i.e. military warfare], striving to achieve a 'combined defense' [strategy]."
In a Sobh-e Sadeq article titled "The Role of the Basij in the Passive Defense [Plan]," Jalali described the preparations being carried out as part of this plan, and stressed the pivotal and vital role of the Basij in its implementation:
"Iran's passive defense [doctrine encompasses] all measures that [can] minimize the danger to the country and its stability, and do not involve the use of arms. In light of the threat to [our] political regime, we must reinforce the stability of this regime through effective [measures of] passive defense. [In fact], there are four elements whose vulnerability to an enemy [attack] must be minimized: the regime, the government, the people, and the defense [i.e. the armed forces]. The regime is the main [authority] that has the ability to administer [the country], provide the [citizens'] needs, and [maintain] the contact between the top leaders, the government and the people. The government [maintains] the infrastructures [and provides services] like sanitation, health care, energy, food, information, security etc... [And] the people are the target of the enemy's [psychological warfare]... The defense [i.e., the armed forces] is not part of this discussion...
"Managing the crisis resulting from war - i.e., administering the country's [home front], provinces, cities, neighborhoods, apparatuses and organizations... - is considered an extremely difficult [task]. We believe that the solution to this problem lies in relying exclusively on the abilities of the Basij. In fact, the Basij is indirectly responsible for the management [of the home front] in time of war, and this is its vital role. Luckily, Iran is one the few countries that has an organized Basij force. In order to enable the Basij to manage [the home front] on a national level, in coordination with the Interior Ministry and with the authorization of the President's Office, a region-based apparatus has been established, known as the regional Passive Defense councils. These [councils] are under the authority of the province governor, and of the Revolutionary Guards and Basij [forces, which are likewise under his authority] and which aid him in matters of passive defense.
"As part of these councils, eight work groups have been formed in several provinces, dealing with threats, intelligence, crisis management, sanitation, health care, etc... and efforts are underway [to form similar councils] in other provinces as well... Another step that has been taken is to familiarize the various government ministries and their apparatuses with the Passive Defense Organization...
"The first task of this organization is to gain professional knowledge of the enemy and of the threats he poses. Threats exist in every domain, and this must be taken into consideration. In every [passive defense council], there must be a team that is responsible for identifying potential threats and dangers, and this team must consist of experts.
"The [organization's] second task is to work in coordination... with the Basij. In other words, they must enter the scene and take part [in operations].
"The third task is crisis management, [because] the various mechanisms and organizations [must continue] to function in times of war. Maintaining contact between the leader [Khamenei] and people - [which is crucial] to the people's sense of security - is carried out by means of the [Iranian] broadcasting service, so technical [measures must be taken] to minimize the vulnerability of this establishment. Other apparatuses and ministries must maintain the same level of readiness, [so that] Basij [members] can replace [absent employees] and do the [necessary] work. This does not require a [special] decree - the Basij will act spontaneously [as needed].
"The fourth task is information management. The responsibility for guiding the public rests with the Broadcasting Agency, the universities, the Culture and Education Ministry and with other relevant organizations.
"The fifth task is maintaining security and protecting [sensitive information]. This is carried out independently at the city level, and is the responsibility of the police and other relevant apparatuses. The [ultimate] responsibility rests with the government ministries and agencies, but the Basij must also help [with this task]. And [since] the enemy places special emphasis on the use of a 'fifth column' and agents, the Basij must be alert. If a certain facility is [attacked], the Basij must immediately take control of it and prevent people from entering it." (footnotes omitted)
UPDATE: Iran has nine oil refineries. Someone else noticed this earlier. As did Britannica Blog here, which is an excellent read, though they count 10 refineries on their map which is reproduced nearby.
Warfare is so scalable.
UPDATE2 (12 July 08): The Basij:
The Pasdaran was given the mandate of organizing a large people's militia, the Basij, in 1980. Islamic Revolution Guards (Vezarat-e Sepah Pasdaran-e Enqelab-e Islamic) is in charge of the paramilitary national Mobilization of the Oppressed (Baseej-e Mostazafan) Organisation. It is from Basij ranks that volunteers were drawn to launch "human wave" attacks against the Iraqis, particularly around Basra.
The Basij, or Baseej paramilitary volunteer forces, come under the control of the Revolutionary Guards. They have been active in monitoring the activities of citizens, enforcing the hijab and arresting women for violating the dress code, and seizing 'indecent' material and satellite dish antennae.
The Basij Resistance Force appeared to be undergoing something of a revival under the administration of President Mahmud Ahmadinejad. This could be connected with the organization's alleged role in securing votes for Ahmadinejad during the presidential campaign and on election day. Ahmadinejad appointed Hojatoleslam Heidar Moslehi, the supreme leader's representative to the Basij, as an adviser in mid-August 2005. But the revival -- along with changes in the paramilitary organization's senior leadership -- could also be connected with preparations for possible civil unrest. In late September 2005, the Basij staged a series of urban defense exercises across the country. General Mirahmadi, the first deputy commander of the Basij, announced in Tehran that the creation of 2,000 Ashura battalions within the Basij will enhance Iran's defensive capabilities. Ashura units have riot-control responsibilities.