I don't want to go into training techniques too much here in this section, as the Mods prefer it in the Training sections... But, if the dog is dog reactive, and you are using a prong collar to "manage" him, you are only making things worse. Prongs used in that type of environment only cause the dog to have more aggression, and teach it to mask it's normal cues to let you know he is not comfortable in that situation. Any trainer that would suggest using a prong without trying MANY other forms of positvie reinforcement techniques on a dog reactive dog has no business calling themselves a trainer. That's the sad reality though, anybody can call themselves a dog trainer...many believe in Alpha theory and dominance. Look at Ceasar Milan...no credentials, and not qualified to be a behaviorist or trainer, no clue about dog body language, etc, but he still calls himself one and so many people try his "techniques". Look where that got him (See this Thread
viewtopic.php?f=6&t=146839&start=30 on page 3, 3rd post down).
As for your leash reactivity, check out this recent thread with another member going through the same thing as you. Maybe it will be of some help...
viewtopic.php?f=6&t=154272It is nice to have you here Eddie! That's my Unlces name

I'm also in the IT field, but I do more of Systems and Network Admin type stuff.