var/A = src.client.address
src << "I am sorry, but you are ip banned."
del src

BannedIP = list()

switch(alert("Are you sure you wish to ban [M]/[M.key]?","Confirmation","Yes","No"))
var/A = M.client.address//Copys the IP

Problem description:
Alright, those are really the only segments of code you need to see. If it is at ==1 it doesn't let me, the host connect. If I do ==0, it won't let others connect.

You're using findtext on a list, which doesn't quite work! You want to use Find instead.

Also, Find (and findtext) returns the index of the found item, and 0 if nothing is found. So you don't want to use if(find()==1) - you want to use if(find()).
In response to Elation
Or even better, he could use in since the position doesn't matter to him.

if(A in BannedIP)
In response to DarkCampainger
Well, I could do that, but I am debating on whether or not to use copytext on the ip range so I can range ban. And I do know why it was banning me for ==0...It was because it doesn't see my ip address because I'm host. Thanks, both of you. I will test these when I get back home on the computer that has the dme file on it.