From a hilltop on the outskirts of Kalkilya, the soldiers of the 55th Artillery Battalion can see the lights of Tel Aviv shimmer in the distance. It is a constant reminder to them of the importance of their mission. Just 12 kilometers separate Kalkilya from the Mediterranean Sea. In between lie the cities of Kfar Saba, Ra'anana and Herzliya. Netanya and Hadera aren't far off. This is Israel's narrow waist, hemmed in by the sea and the West Bank. It was once afflicted by continuous terrorist infiltrations but has enjoyed years of relative calm. The quiet is deceptive, though, and the threat of terrorism has not dissipated. In the Palestinian border areas adjacent to the Sharon district, right under the nose of the IDF, Hamas seeks to establish a foothold, and with it the potential for renewed attacks. Crossing into the West Bank from central Israel involves a dramatic change in scenery as one leaves the Trans-Israel Highway (Route 6) and climbs to the Tzofim checkpoint in the rugged, rustic hills of the West Bank, east of Kfar Saba. With another day of work in Israel behind them, Palestinian farmers on donkey-drawn carts join a stream of vehicles from the Palestinian Authority at the Eliyahu vehicle crossing, where they must cross back into the West Bank. A number of smaller checkpoints for pedestrians dot the security fence around the crossing. The military says the security fence has greatly helped in stopping terrorist raids from the West Bank. If touched, electronic sensors on the fence will sound an alert, and army vehicles will arrive in minutes. Footprints in the sand deliberately placed alongside the fence help lead trackers in the infiltrators' direction. A month ago, soldiers spent the entire night looking for two infiltrators who had wised up and covered their tracks after crossing into Israel. "They usually infiltrate for work purposes, but the fact is we never know why they've crossed until we capture them," a military source told The Jerusalem Post during a tour of the area. "We have a double challenge here: to secure Israeli residents while ensuring swift passage for Palestinian workers without impinging on their dignity," he added, as he stopped his jeep to let a group of young Palestinian men cross the street. One of the men waved his thanks. Still, local youths often "test" the troops, the source said, citing attempts to cross illegally, as well as rock throwing incidents. To counter this, the army conducts a dialogue with Palestinian community elders, asking their help in keeping the youths under control. As we drove deeper into the Palestinian territories, a large roadside poster advertised the newly-launched Al-Quds satellite television channel, Hamas's second TV station. "Hamas operates here," the source acknowledged. "Three days ago, an Israeli man came here to purchase something in a Palestinian store and was shot in the chest and leg," he added, without directly tying the shooting to a specific terror organization. The man is recovering from his wounds at Meir Hospital in Kfar Saba. Soldiers from the 55th Battalion, which has been in charge of the area for five months, helped capture the gunman. "We close off the house, surrounding it quietly," the source said of the method. "The family is woken up and asked to bring the suspect to the door. Suspects usually comply; they know they're surrounded and they prefer to get out alive." The army aims to make the movement of ordinary Palestinian workers as smooth and swift as possible, according to the source. No more than a few minutes' delay at the checkpoint is the goal. "We want to achieve a minimal level of friction between Palestinians and soldiers," he said. To achieve this, the crossing points have been equipped with a computer system that automatically grants or denies entry to Palestinians based on their ID numbers. "The soldiers know they don't have to make a decision on entry," the source explained. "It's not up to them." Instead of being frisked, Palestinian pedestrians walk through a weapon detector similar to that at an airport. Next, their ID cards are dropped through a slot and picked up on the other side of a glass divider by a soldier, who runs the ID numbers through a computer hooked up to the IDF's network. Unless the computer shows that he is barred from crossing into Israel, the pedestrian should be on the other side within about two minutes. At the larger Eliyahu crossing, vehicles are stopped and searched by Military Police officers, who are guarded by the men from the 55th Battalion. The army does not want drivers to have to wait more than five minutes, the source said. "Look over there," he said, pointing to Palestinians walking into the West Bank and passing by Israeli hitchhikers. The hitchhikers were heading back to their homes in the settlements of Karnei Shomron and Sha'arei Shomron. "If the settlements weren't there, this border would be like any international border, like with Egypt or Jordan," the source said. "[But] we must protect the settlements [too]." The Sharon District has been spared the rockets that have terrorized Sderot and Ashkelon, he said, because, unlike in Gaza, the IDF was on the ground in the West Bank, constantly keeping watch and moving in when necessary. In between their duties of securing the Sharon district, the men of the 55th Battalion must also find time to train for their wartime role, which is manning canons and artillery guns. The battalion, which took part in the Second Lebanon War, regularly trains to "keep their skills honed," the source explained. "We have to be ready for every eventuality."