Port function and scanning

Cheswick on firewalls is a bit outdated, but a good start.

How would you know? Do ou trust the answers you get here more than someone witha webpage?

Take a second PC and use nmap.

Cheers, Jens

RFC 793 ff.

Definitely not.

Start here:

Try

-Gary

Ports are a concept being part of the TCP/IP protocol family. This has nothing to do with Windows. Just read the RFCs, or try Richard Stevens' "UNIX Network Programming".

You could start here, too:

Better scan yourself, i.e. using nmap. Port scanning web services are b0rken by concept, because they cannot determine, if your machine has open ports or if the network in between modifies traffic.

Yours, VB.

Dear Volker,

Thank you for your attenti>Better scan yourself, i.e. using nmap. Port scanning web services are

I am not familiar with programming and related tasks. I have been burned recently by malware and want to make sure it does not happen again.

A Symantec scan has recently shown that all my parts are secure, except the "ping" port, whatever that means.

Your advice to use nmap seems to be a good one and I would like to use it. There is however a learning curve involved. Before I climb it, I would like to make sure nmap will serve my purpose. I have a stand alone PC connected to the net through an ISP. Can I use such a configuration to scan my own ports?

Greet> > 1. Is there a good internet document describing ports, their

Well, if you're not, then you should not fiddle around with network-related tasks. Pay a competent service for doing so.

Yes, that shows exactly what to think about this POS.

Now even that should be clear to someone with almost no networking experience: No. Scanning involves sending requests and receiving replies, now that's where you need a second machine (or someone carefully bouncing all traffic forth and pack, but you won't any such machine).

That's why I recommended . This is more or less an interactive web service for Nmap, even though it's a little bit outdated.

If you have a friend running Linux, or is prepared to run a 'Live' Linux off a CD on his machine (DSL is probably the simplest), you could give him your ipaddress (run 'ipaddress' from a windows console) and get him to scan your machine with nmap.

Jim Ford

There is a version for nmap on windows.

Cheers, Jens

Dear Jim,

Is the proper command for finding one's IP address not 'ipconfig' run from the command prompt?

I don't get a result for putting in 'ipaddress'.

Than you GR.

Yes, that is one of the possible ways.

Dear Sebastian,

I do not follow some of your writ> >A Symantec scan has recently shown that all my ports are secure,

Now I still do not know what to think and I also do not know what a POS is.

You advised me to use

This service however requires me to install nmap, something which you advised me a few paragraphs earlier not to do by stating:

network-related

Best regards GR.

No it doesn't.

It says: "You should download and install nmap from

"You should download and install nmap".

Your scan result is a bit further down on the same page.

Greetings, Jens

Yes - sorry!

"pile of s*it"

No, it doesn't. Why do you think so? This service offer you an online port scan with Nmap, by your command line (with some filtering) as input and the full Nmap output as the output.

Keep console closed and don't type commands you are not familiar with. Check this site.

"NoSpam" wrote in news:tNzfi.1444$s%.606@trnddc02:

A neat little program for Windows is IP2 by Robin Keir. It even shows your computer's lan IP and WAN IP if you are behind a nat router. It's all of 8K size for zip download. Extracted to disk the .exe file is 14K. There are no other files involved nor created by the program later.

Dear John,

Great suggestion, BUT how can one be sure that the software is safe?

GR.

To understand, that a port just is a maintainance number, and what it's for, it could be a good idea to change that a little bit.

It means nonsense. There is no such thing like a "ping port". Why I'm not surprised to find horseplay in a Symantec's text? ;-)

In such a configuration, you don't need any port scanner at all. Just use the netstat command to determine, which ports are used by which processes.

Yours, VB.

"NoSpam" wrote in news:gNGfi.3282$cV.1286@trnddc04:

I've used several of his utilities, including K9, a Bayesian antispam POP3 local proxy. All are small, and I've never had malware. I've received infected email messages, and the antivirus has alerted on things downloaded to the browser cache but I've never been infected. I regularly check with AVG, AVG Anti-Spyware, AVG Anti-Rootkit, AdAware, and Spybot Search & Destroy. I trust all his software completely.

Of course, because you don't really know me, all this may mean nothing to you and I can understand some skepticism. I'm the same way, and can't help it. Search around and check out Robin Keir's reputation. I think you'll feel comfortable after a thorough check. He participates regularly in GRC usenet, especially GRC.Spam, GRC.security, and GRC.privacy. The server is news.grc.com and after reading a few threads there you'll be more comfortable about the safety of these programs. Especially, look at Hash on keir.net as it's great for checksums on files