Security Basics mailing list archives
RE: verifying an open or closed port on an ip address
From: "Simon" <simon () snosoft com>
Date: Sun, 10 Aug 2003 23:42:44 -0700
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Howdy, Well, there is always netcat which is quite literally the leatherman of networking. You can do just about anything with it including connecting to tcp and udp ports, forging packets, listening to certain ports... etc etc.. ;) - -----Original Message----- From: Norberto Meijome [mailto:sysadmin () lef com au] Sent: Thursday, August 07, 2003 6:03 PM To: security-basics () securityfocus com Subject: RE: verifying an open or closed port on an ip address *** PGP Signature Status: bad *** Signer: Norberto Meijome (beto () sharmannetworks com) <Sharman Networks> (Invalid) *** Signed: 8/7/2003 6:02:55 PM *** Verified: 8/10/2003 11:39:58 PM *** BEGIN PGP VERIFIED MESSAGE *** True, telnet is probably the easiest way to check...but since telnet is a TCP connection, it would only report TCP ports...if you want to test if you have something waiting on port UDP/677 you will need some of the other tools (send UDP packet, and then wait for a reply). Also, don't forget that depending on your firewall settings, you could get a 'not listening' from where you are testing, but the same port could be open to traffic originated from another IP. To be thorough, you should run the full test (with the port scanning tool of your choice) from your LAN, DMZ and outside your firewall. (of course you should know what your firewall is doing, but testing to confirm is always good). Cheers, Beto - -- Norberto Meijome "The only people that never change are the stupid and the dead", Jorge Luis Borges. NOTICE: The contents of this email and its attachments are confidential and intended only for the individuals or entities named above. If you have received this message in error, please advise the sender by reply email and immediately delete the message and any attachments without using, copying or disclosing the contents. Thank you.
-----Original Message----- From: David Bettermann [mailto:security_01 () nerv de] Sent: Friday, 8 August 2003 8:07 AM To: security-basics () securityfocus com Subject: Re: verifying an open or closed port on an ip address Hi Ian,I am looking for a windows compatible utility or method, preferably command line, where I can verify whether a port on an ip address is reachable or not. I want to be able to do individual ports and not port scans. Say for instance I wish to verify that port677 is closedto traffic on ip address Ex. 172.16.0.1, I'm looking for a utility that would do something like:Check 172.16.0.1 port 677how about a quite simple "telnet 172.16.0.1 677" issued from the command line?and tell me whether that port was reachable.Command times out / reports an error: port closed Telnet connects: well, there's something listening on that particular port... and may even be greeting you with an identifying banner. [...]There may be a simple way to do this...maybe someone's got an even simpler solution? cu :) David B. -- Thank you for calling $PROVIDER helpdesk. If your cupholder is broken, please press 1. If you want an actual knowledgable support person, please enter the IP representation of a /28 netmask. -------------------------------------------------------------- ------------- -------------------------------------------------------------- --------------
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Current thread:
- verifying an open or closed port on an ip address (Aug 07)
- Re: verifying an open or closed port on an ip address David Bettermann (Aug 07)
- RE: verifying an open or closed port on an ip address Norberto Meijome (Aug 08)
- RE: verifying an open or closed port on an ip address Simon (Aug 11)
- RE: verifying an open or closed port on an ip address Norberto Meijome (Aug 08)
- RE: verifying an open or closed port on an ip address Jason Coombs (Aug 08)
- RE: verifying an open or closed port on an ip address Simon (Aug 11)
- Re: verifying an open or closed port on an ip address Birl (Aug 11)
- Re: verifying an open or closed port on an ip address James Fields (Aug 11)
- Re: verifying an open or closed port on an ip address Kajetan Sikorski (Aug 12)
- <Possible follow-ups>
- RE: verifying an open or closed port on an ip address Tony Kava (Aug 07)
- Re: verifying an open or closed port on an ip address Bradley Adams (Aug 07)
- RE: verifying an open or closed port on an ip address Chris Wanstrath (Aug 07)
- RE: verifying an open or closed port on an ip address Rubottom, Karl (Aug 11)
- Re: RE: verifying an open or closed port on an ip address (Aug 12)
- Re: verifying an open or closed port on an ip address David Bettermann (Aug 07)