Nmap Main Scan types -sR

RPC scanning (-sR)

RPC scanning method always works in combination with several of port scan methods of Nmap.  The idea of this is that try to determine the target ports are RPC ports or not.  Decoys are not used in RPC scanning.

#nmap –sR –v 10.50.1.254

Starting nmap V. 2.54BETA30

Host vpn1-gw.lab.tct.hut.fi (10.50.1.254) appears to be up ... good.

Initiating Connect() Scan against vpn1-gw.lab.tct.hut.fi (10.50.1.254)

Adding open port 23/tcp

Adding open port 80/tcp

Adding open port 139/tcp

Adding open port 1723/tcp

Adding open port 24/tcp

Adding open port 515/tcp

The Connect() Scan took 1 second to scan 1549 ports.

Interesting ports on vpn1-gw.lab.tct.hut.fi (10.50.1.254):

(The 1543 ports scanned but not shown below are in state: closed)

Port       State       Service (RPC)

23/tcp     open        telnet                 

24/tcp     open        priv-mail              

80/tcp     open        http                   

139/tcp    open        netbios-ssn            

515/tcp    open        printer                

1723/tcp   open        pptp                   

Nmap run completed -- 1 IP address (1 host up) scanned in 1 second

Nmap Scanning and security basics.

The first step of attacking is to get as much information as possible for the target network. An attacker would find bugs of different OSs and available services. This can be done by a toll called scanner. Scanning can be made manually, but it is much easier to automate scanning with scanner tools such as SATAN(Security Administrator’s Tool for Analyzing Networks), Nessus, Nmap and so on.

 Scanners query TCP/IP ports and record the target’s response. They glean valuable information about the target host by determining

. What services are currently run?

. Who owns those services?

. Whether anonymous logins are supported

. Whether certain network services require authentication

Port and port scanning

Port is an access point for an application running on a computer system. All Internet and TCP/IP based networks require a source IP address, destination IP address and source port as well as destination port. There are three kinds of port, which are well-known ports, registered ports and dynamic (private) ports. The well-known ports range from 0 to 1023, the registered ports are those from 1024 through 49151, the dynamic (private) ports are those from 49152 through 65535.

Port scanning uses some specific tools, like Nmap, to automate the identification of active ports on a target system.

Finger printing scanning

Fingerprinting is a technique that tries to identify the target system operating system.  The technique helps an attacker to ascertain each target system host’s OS with a high probability. Once the target system OS is identified, the attacker can concentrate on his effort to compromise it.

what is Proxy Searver

A server that sits between a client application, such as a Web browser, and a real server. It intercepts all requests to the real server to see if it can fulfill the requests itself. If not, it forwards the request to the real server.

Proxy servers have two main purposes:

Improve Performance: Proxy servers can dramatically improve performance for groups of users. This is because it saves the results of all requests for a certain amount of time. Consider the case where both user X and user Y access the World Wide Web through a proxy server. First user X requests a certain Web page, which we'll call Page 1. Sometime later, user Y requests the same page. Instead of forwarding the request to the Web server where Page 1 resides, which can be a time-consuming operation, the proxy server simply returns the Page 1 that it already fetched for user X. Since the proxy server is often on the same network as the user, this is a much faster operation. Real proxy servers support hundreds or thousands of users. The major online services such as America Online, MSN and Yahoo, for example, employ an array of proxy servers.

Filter Requests: Proxy servers can also be used to filter requests. For example, a company might use a proxy server to prevent its employees from accessing a specific set of Web sites

How is a server different from a desktop? What are storage area networks? Can I use a high-end desktop in place of a server?

How do you know when you need a server? proxy server Do I need more than one server?

How much memory and disk space will it need? Will I have to replace it in six months? How much will a server cost?