Israel engaged in an imaginary war this week, as security forces conducted the largest civil defense exercise in the country's history. Thousands of policemen, soldiers from the IDF's Home Front Command, Fire and Rescue Services personnel and Magen David Adom medics held a number of drills testing their response to a wide range of threats, from 9/11-style attacks to Iranian and Syrian non-conventional missile strikes. As elite policemen threw stun grenades to neutralize terrorists who took over a school in Ramat Gan, soldiers in special chemical and biological protective suits treated civilians who had been wounded in sarin gas attacks. The two-day exercise was not the only defense training going on this week. In the Golan Heights, Armored Brigade 401 took its Merkava 4 tanks into the hills, dodging imaginary Hizbullah and Syrian anti-tank missiles and sharpening skills ahead of a potential war. In the South, the IDF was training ahead of possible action in the Gaza Strip. In the midst of all of this, Gabi Ashkenazi marked a month since taking up his post as the IDF's 19th chief of General Staff. Instead of celebrating, he spent his time presenting his vision for his four-year term at a convention of the senior brass, and touring the civil defense exercise with Defense Minister Amir Peretz. Ashkenazi is keeping a close eye on the increased IDF training. During his visit two weeks ago to the Tze'elim training center, officers said they already noticed the difference between Ashkenazi and his predecessor, Dan Halutz, who resigned two months ago following public criticism of the IDF's failures during the second Lebanon war. "He asks questions about the tiniest details," one officer who was present at the exercise said. "These are questions that only people who grew up in the infantry would know to ask." Ashkenazi is also holding diplomatic-military meetings. Last week, he met with Italian Chief of Staff Adm. Giampaolo Di Paola for talks on Italy's enhanced role in the command of UNIFIL, and ways to better enforce Security Council Resolution 1701 in southern Lebanon. Next week, he will meet with the Polish chief of staff, who will be here with Defense Minister Aleksander Szczyglo to discuss issues of cooperation with the defense establishment. ON THE whole, however, Ashkenazi is remaining quiet. He has yet to meet with the media, and even after Monday's convention with the brass, he warned officers against leaking information to the press, and ordered the IDF Spokesman's Office not to brief reporters on his hour-and-a-half speech. Officers close to him claim that for the moment he doesn't have much to say, but rather is busy overseeing the rehabilitation of the IDF, including an increase in training and restocking of warehouses. Unlike Halutz, who led a process of cutting back on reservists and their training, Ashkenazi has declared that "reservists are the primary source of the IDF's strength," and spoken about the need to rebuild relationships of trust with them. His main message has been one of stability. While he is a known and vocal opponent of Halutz's decision to reform the Ground Forces Command and turn it into the IDF's largest branch, Ashkenazi is holding back on reverse reforms, so as not to send the military into shock so soon after the war. Since taking office, he has made only small changes in the organic structure of the IDF. One example is his decision to return authority over the appointment of brigade commanders to the General Staff from the Ground Forces Command. Ashkenazi is also leaning toward returning the Logistics Division from the GFC to the Logistics and Medical Branch - where it was before Halutz took office and decided to beef up the GFC and create a military of three branches: ground, sea and air. Halutz's reforms did not prove themselves during the war, however, and a high-ranking officer in the Logistics and Medical Branch admitted this week that there has been increased talk about shifting the Logistics Division back to the branch. Sources said that Brig.-Gen. Eran Ophir, head of the West Bank security fence in the IDF and formerly Ashkenazi's chief logistics officer at Northern Command during the withdrawal from Lebanon in 2000, is serving as a consultant to the chief of General Staff on military-logistic affairs. "The new system failed during the second Lebanon war," explained a military source. "The idea now is to recreate a single branch in the IDF that will be responsible for synchronizing everything that has to do with logistics and supplies." ASHKENAZI IS a tough, demanding commander. He calls meetings with his staff early every morning, and tries to spend most of his time in the field, rather than in his office in Tel Aviv. He has high expectations when it comes to discipline, and has ordered the Military Police to crack down on soldiers caught hitchhiking, particularly in the West Bank, where there is a fear they will be kidnapped by terrorists. Not everything will wait for Ashkenazi, however. One of the more pressing issues on his table is creating a new General Staff, filling slots with officers not tainted either by their relationship with Halutz or by the war. These appointments are crucial, since these generals will be the main decision-makers when it comes to the IDF's current challenges: Iran, Syria, Hizbullah and Hamas. The changes will need to happen in the near future, as a number of senior officers are scheduled to retire. OC Central Command Maj.-Gen. Yair Naveh has asked to retire. OC Home Front Command Maj.-Gen. Yitzhak (Jerry) Gershon, who had hoped to replace Naveh, might now also be looking at retirement because of the publication of a State Comptroller's report - said to be highly critical of him - on the maintenance of the home front during the war. Naveh has said that he would stay in the IDF if he were offered the post of deputy chief of General Staff or OC Ground Forces Command. Its current head, Maj.-Gen. Benny Gantz, is vying to become Ashkenazi's deputy. He is up against Maj.-Gen. Dan Harel, now the military attach in the US and a close friend of Ashkenazi's. OC Human Resources Maj.-Gen. Elazar Stern will also be wrapping up his military career in the summer. He has expressed interest in entering politics, on a national or municipal level. OC Military Intelligence Maj.-Gen. Amos Yadlin is waiting for the verdict of the Winograd Committee to know whether he will remain in the IDF. There are also questions surrounding the future of Deputy Chief of General Staff Maj.-Gen. Moshe Kaplinsky, following his defeat in the race to replace Halutz. He has not hidden the possibility that he might also retire and go into business, or make a bid to replace Mossad chief Meir Dagan when he finishes his term in 2008.