ok korrijanme si me ekivoko .. kon esta esplicaion que dan kiere decir que puedo hacerme pasar por una ip que esta dentroe del ramgo de ip del server  .... ejemplo

consigo info del server ...

xxx.xxx.xxx.x18

Resolving host www.something.com.mx
Resolved as : xxx.xxx.xxx.xxx
NETBIOS discovery ...
Done sending, waiting for responses ...
SNMP discovery ...
Community string : public
Done sending, waiting for responses ...
ICMP sweep ... (PING!)
Done sending, waiting for responses ...
PONG from xxx.xxx.xxx.xxx
- Time to live (TTL) = 124 (128)
  + 4 hop(s) away
- ICMP code in response = 0 => Windows box
- Timestamp Reply (200.33.136.18)
- ICMP UNREACH for closed port (xxx.xxx.xxx.xxx)
Ready
1 Computer(s) found.

[xxx.xxx.xxx.xxx]
Resolving xxx.xxx.xxx...

Resolved as : customer-xxx.xxx.xxx.xxx.uninet.net.mx
UDP scanning thread started ...
TCP scanning started ...
12 open port(s).
Gathering banners ...
80 - Trying to determine web server type
Server : Microsoft-IIS/5.0
Operating System : Windows 2000
Anonymous logins accepted ?
No
8080 - Trying to determine if we have a web server here

UDP scanning thread stopped.
SMB probing ...
Connecting ...(1/6)
Name "CUSTOMER-xxx-xxx-xxx-xxx" encoded as "EDFFFDFEEPENEFFCCNDCDADACNDDDDCN"
Session refused : File sharing and printing is not activated!?
NULL session refused.

Alerts probing ..
Checking FTP Alerts ...
Checking DNS Alerts ...
Checking Mail Alerts ...
Check for EXPN/VRFY commands ...
250 Root User<root@something.somethingmore>

250 Root User<root@>

Checking Service Alerts ...
Checking RPC Alerts ...
Checking Miscellaneous ...
Checking Information ...
CGI probing ...
Please wait ...
- Frontpage check (2)
/_vti_bin/shtml.exe
Too manny timeouts. Aborting ...
CGI probing finished.

pruebo rango de ip´s

? xxx.xxx.xxx.xx2 : custumer xxx-xxx-xx2. uninet.net.mx
? xxx.xxx.xxx.x18 : Custumer xxx-xxx-x18.uninet.net.mx
ese 18 es la ip scaneada arriba ..
luego algo interesante ... SISCO 2509
SISCO xxx.xxx.xxx.x19 : host-victima.something.net.mx
3com xxx.xxx.xxx.x86 : LanMismaEmpresa
SISCO xxx.xxx.xxx.127 : Host-victima.something.net.mx

escaneo sisco x19 y tengo hasla los loguins.... pero no pertenerco a el rango de ips del server ... pero segun entiendo .. corrijanme porke soy newbie ... komodice okahei .. puedo tener

xxx.xxx.xxx.x18 y pasar para xxx.xxx.xxx.x19 ??¿¿¿