Investigating a phishing complaint

UPDATE: Seems it was a fake email, so not really that urgent, but the questions are still valid.

So I received an email about a VPS I host (I'm a VPS hosting company, this is a customer VPS) being used for phishing sites, on both IPs for the VPS, and I'm wondering what to do. I tried setting local hosts file such that I'd be seeing their phishing site, but didn't seem to work, and no I didn't do it wrong :P

Anyway, that aside, at the moment I'm grepping the whole openvz directory for the particular domain, however nothing has come up.

So I guess what I'm wondering is:

1. Is there some cool fancy tool I don't know about that lets you check if an IP:[port optional] answers to a vhost/domain? (maybe needs a 2nd question for that? :) )
2. This VPS is running nginx, what should I be looking for (at the moment all I see is some proxy stuff to vk.com, maybe the phishing email I got is old?)

3. Any other advice.

   cat /etc/nginx/conf.d/default.conf
   server {
       listen xxx.xxx.199.213:30;
       server_name redirectvk;
       access_log /dev/null;
               location / {
                 proxy_bind xxx.xxx.199.213;
               proxy_pass http://vk.com:80;
               }
       }
   
   
   server {
       listen xxx.xxx.199.213:31;
       server_name redirectlvk;
       access_log /dev/null;
               location / {
               proxy_bind xxx.xxx.199.213;
               proxy_pass http://login.vk.com:80;
               }
       }
   
   server {
       listen xxx.xxx.199.213:32;
       server_name redirectmvk;
       access_log /dev/null;
               location / {
               proxy_bind xxx.xxx.199.213;
               proxy_pass http://m.vk.com:80;
               }
       }
   
   
   server {
       listen xxx.xxx.199.213:80;
       server_name redirectvk;
       access_log /dev/null;
               location / {
               proxy_set_header Host $host;
             proxy_bind xxx.xxx.199.213;
               proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
               proxy_pass http://5.9.90.49:80/;
               }
       }
   
   
   
   
   server {
       listen xxx.xxx.199.214:30;
       server_name redirectvk;
       access_log /dev/null;
               location / {
                 proxy_bind xxx.xxx.199.214;
               proxy_pass http://vk.com:80;
               }
       }
   
   
   server {
       listen xxx.xxx.199.214:31;
       server_name redirectlvk;
       access_log /dev/null;
               location / {
               proxy_bind xxx.xxx.199.214;
               proxy_pass http://login.vk.com:80;
               }
       }
   
   server {
       listen xxx.xxx.199.214:32;
       server_name redirectmvk;
       access_log /dev/null;
               location / {
               proxy_bind xxx.xxx.199.214;
               proxy_pass http://m.vk.com:80;
               }
       }
   
   
   server {
       listen xxx.xxx.199.214:80;
       server_name redirectvk;
       access_log /dev/null;
               location / {
               proxy_set_header Host $host;
             proxy_bind xxx.xxx.199.214;
               proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
               proxy_pass http://5.9.90.49:80/;
               }
       }
   

Thanks!

(also how did ladadada get the config post to look so nice, mine went all fubar :?)