Re^3: Telnet list of IP and get information stored to a file

The list has some 300 IP address or network. It means so many thousands of IP address

I wonder what reason one could have to try a port scan against such a large list. If you legally own (or use) that many systems, you should have a network management system making such strange scans unnecessary. I also wonder why you want to access machines owned by General Electrics (3.0.0.0/8) and the United States Department of Defense (22.0.0.0/8).

I don't know how nmap would be useful here.

Well, perhaps you should start reading the nmap documentation. nmap can be configured to scan entire net blocks. It can be configured to scan only one or a few selected ports. It can read a list of scan targets from a file. It can be configured to scan by establishing a TCP connection. It can scan in parallel. And it can be configured to do all this at once. And of course, nmap can write a report in various formats, like XML, HTML and plain text. nmap is the wheel you want to reinvent (and much more).

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)

Comment on Re^3: Telnet list of IP and get information stored to a file

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Re^4: Telnet list of IP and get information stored to a file by sanju7 (Acolyte) on Jul 26, 2010 at 22:03 UTC
I must clarify here IP addresses are fictitious, my bad i should have symbolized it properly. I just choose the digits came to my mind by repeating them in each block. The reason for doing telnet it to count the presence of valid application which listens to a certain port. Thats generally easy when doing only few ip addresses. The reason to scan blocks of IP is because its not clear which ip in network is available(up and on) i.e basically simplify the search. (a)If its valid system then would respond to telnet / port (b) if not then it would quit In general its a reporting work should have been reported by some other way (but as circumstance required information which i was trying to get), as in a application which is present in many places largely separate remote networks it seems easy to telnet a certain port of a server staying within org network rather than connecting each GUI of the each app remotely etc and check manually	[reply]
Re^5: Telnet list of IP and get information stored to a file by afoken (Chancellor) on Jul 27, 2010 at 11:47 UTC
The reason for doing telnet it to count the presence of valid application which listens to a certain port. Does that application speak the telnet protocol (RFC 854) or do you just need a connect scan? For the latter, get rid of Net::Telnet and use IO::Socket instead. I think you are confused by the fact that many telnet client implementations automatically and silently switch to a more or less raw mode when they can connect to a port, but cannot negociate a telnet connection. This happens for example when you telnet to an HTTP or SMTP server. The reason to scan blocks of IP is because its not clear which ip in network is available(up and on) i.e basically simplify the search. Use nmap for that. Tell nmap to scan a list of IP addresses or IP ranges from a file with a simple TCP connect scan on the application's TCP port. Leave the ping scan enabled to sort out machines that are down, disable the ping scan if the machines are stupidly configured not to respond to ping requests. nmap will deliver you a list of all hosts that are in the list of IPs and can be connected on the application port. Alexander -- Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)	[reply]