不知道这是否仍然需要，但想与我分享我的解决方案：

1）安装django-tracking（感谢你的贴士Van Gale Google Maps + GeoIP很棒！）

2）添加此中间件：

from django.contrib.sessions.models import Session
from tracking.models import Visitor
from datetime import datetime

class UserRestrictMiddleware(object):
    """
    Prevents more than one user logging in at once from two different IPs
    """
    def process_request(self, request):
        ip_address = request.META.get('REMOTE_ADDR','')
        try:
            last_login = request.user.last_login
        except:
            last_login = 0
        if unicode(last_login)==unicode(datetime.now())[:19]:
            previous_visitors = Visitor.objects.filter(user=request.user).exclude(ip_address=ip_address)
            for visitor in previous_visitors:
                Session.objects.filter(session_key=visitor.session_key).delete()
                visitor.user = None
                visitor.save()

3）确保它位于VisitorTrackingMiddleware之后，你应该发现当有人新登录时以前的登录会自动被破坏:)