How to tell which ports are open or in use?

Message

rcrsn51 · #21 Post by **rcrsn51** » Wed 22 Jun 2011, 23:03

Win9x came with Microsoft's own JVM, but they were sued by Sun for not fully implementing the Java standard. MS lost and quit including Java by 2003.

gcmartin · #22 Post by **gcmartin** » Thu 23 Jun 2011, 01:33

Its really obvious for most on how to scan your LAN using AngryIP.. Straight away easy!

But, Its not obvious to some, how to use AngryIP for port scanning. Here's something that some may find useful for Port scanning

But be careful because a large IP range and large port ranges will elongate the time it takes the utility to report its finding on-screen.

Hope this helps

nooby · #23 Post by **nooby** » Thu 23 Jun 2011, 08:12

DPUP5520 no I was not thinking about that one. I trust that
rcrsn51 gave a good answer. Sun was involved.

gcmartin · #24 Post by **gcmartin** » Thu 23 Jun 2011, 14:57

Trying to stay on-topic for this thread. JAVA is a separate topic and is only mentioned to indicate requirements "for AngryIP V3" products.

If you want to understand how MS integrates JAVA (whether its MS-SUN integrated in the OS), either review the OS or look at the Wiki TOGETHER WITH here.

But, maybe someone will start a separate thread on "JAVA on Microsoft" discussion or maybe just "The Merits of JAVA in Puppy" discussion thread..

AngryIP, still today, beats the pants off every other LAN IP scanner I have run across (with the exception of hardware LAN scanners). In and of itself, it is small and very fast.

And, AngryIP continues to be maintained for the OS community. It could be very useful for those of us who have need to scan the LAN for various support reasons.

For All Puppy uses
To see an example on HOWTO Scan see this step
For Puppy users, to get the PET, go here

Hope this helps

greengeek · #25 Post by **greengeek** » Sun 13 Jan 2013, 19:54

Anyone know of a solution that does not require java? (I want to be able to see if any data packets are being sent to a printer of known IP)

rcrsn51 · #26 Post by **rcrsn51** » Sun 13 Jan 2013, 20:26

greengeek wrote:Anyone know of a solution that does not require java? (I want to be able to see if any data packets are being sent to a printer of known IP)

Which Puppy are you using? The recent ones have PeasyPort. Or you can get it here.

For networked printers, you should scan for ports 9100 or 515.

gcmartin · #27 Post by **gcmartin** » Sun 13 Jan 2013, 22:35

removed

greengeek · #28 Post by **greengeek** » Sun 13 Jan 2013, 23:04

rcrsn51 wrote:
greengeek wrote:Anyone know of a solution that does not require java? (I want to be able to see if any data packets are being sent to a printer of known IP)
Which Puppy are you using? The recent ones have PeasyPort. Or you can get it here.

For networked printers, you should scan for ports 9100 or 515.

Thanks. I mostly use Thin Slacko on my work laptop, but for the purposes of this investigation I will use whichever puppy allows me to get the info I need.

Seems it's not quite as sraightforward as I first hoped - apparently I need to make a "passive network tap" (or find a suitably designed/configured hub) so that I can hook my puppy laptop onto the same cable that is going to the printer, before I can guarantee seeing the packets heading for the printer.

Thanks for the peasyport link - at first glance I wonder if that will be able to capture any data packets for analysis? Or is it merely confirming the presence of open ports?

rcrsn51 · #29 Post by **rcrsn51** » Sun 13 Jan 2013, 23:13

greengeek wrote: apparently I need to make a "passive network tap" (or find a suitably designed/configured hub) so that I can hook my puppy laptop onto the same cable that is going to the printer, before I can guarantee seeing the packets heading for the printer.

What is your objective? To trouble-shoot a non-functioning printer?

There should be easier ways to do it than setting up a packet-sniffer.

greengeek · #30 Post by **greengeek** » Sun 13 Jan 2013, 23:36

The reason I'm looking at this sort of technology is that one of my customers has purchased our brand of printer and has asked me to replace it as they say "it has a broken network port".

However, they can ping it, and can access the printers internal web page, so basic network functionality is ok. I am able to communicate directly to the printer via crossover cable from my WinXP laptop, and can ping, access the internal webpage, and print through the network port without problems. The customer insists that there is nothing in their network or print subsystem which could cause print packets to be lost, but I suspect that their print spooler has marked the printer as offline somehow and is not issuing the print data. (customer is a large corporate customer with a distributed network citywide and will not confirm to me what server system they are using but I suspect some form of Citrix /server 2003 combo).

I initially asked them to set up a new IP address and print queue as I suspected the original queue has got itself tied in a knot somehow (I've often seen such things before) but they seem unwilling to do this.

I have also asked if there is any way they could look at the router logs to see if packets were being ignored/dumped (or at least counted maybe - so we could get a feeling for how much data was attempting to get through) but they scoffed at the idea and told me to bring a new printer. (That is an option of course but wouldn't prove much because it would have a different MAC address, and they would set it up with a different IP and print queue anyway, so I would expect that to work, but it's not that helpful in terms of identifying why this is happening)

I was hopeful that I could "hook into" the cable going to the printer and identify what type of packets are being sent to the printers IP address, and see if the printer was simply ignoring them. I realise I need to use a lot of caution on the customers netwrok (and would not use this method without their permission...) but I would like to prove that I can make the technology work at home before attempting to use it at work.

I can start a thread for this if you think that would be better...

gcmartin · #31 Post by **gcmartin** » Mon 14 Jan 2013, 00:46

We'd like to help, but, there seems to be something that is missing in what you share.

Here's my understanding problem:

You say the printer can be ping'd and you say that the printer's webpage can be accessed by your customer. True/false?
You say you are using a cross-over cable. Why are you using a cross-over? Are you not able to use your customer's LAN?
You never mentioned if you could utilize the customer'sprinter from your PC. Can you print?
You don't mention whether the customer has other printers present. Do they and can they print? If so, are any of the present printers the same character as this printer?

My external concern is whether you have sold your customer a device for which your customer does NOT have a broken printer. (I've seen this before, too. And, hopefully, this is not the case.)

Questions
What OS is your customer running? And, can you run the same? If you cannot use your customer's PC, then you need to memic the problem by installing a similar OS on your PC to follow thru on testing.
Also, you mention Citrix. What exactly is your customer printing from?

Should you do capture packets, unless you have been trained on understanding printer languages, I'm not sure how that will help you...asuming you are successful.

Can you provide a bit more clarity on top of what you've already shared?

Here to help

greengeek · #32 Post by **greengeek** » Mon 14 Jan 2013, 09:15

gcmartin wrote:We'd like to help, but, there seems to be something that is missing in what you share.

Here's my understanding problem:[*]You say the printer can be ping'd and you say that the printer's webpage can be accessed by your customer. True/false?

True on both counts.

[*]You say you are using a cross-over cable. Why are you using a cross-over? Are you not able to use your customer's LAN?

Correct - I can not risk connecting my laptop to the customers network at this stage. (maybe later if I have their permission)

[*]You never mentioned if you could utilize the customer'sprinter from your PC. Can you print?

Yes, I can print to the customers printer from my PC (via crossover cable)

[*]You don't mention whether the customer has other printers present. Do they and can they print? If so, are any of the present printers the same character as this printer?

They have no other printers available on this site, however they say they have a number of these printers running correctly on other sites around the city. They say this printer did work correctly for a week before it went "offline" and stopped printing.

My external concern is whether you have sold your customer a device for which your customer does NOT have a broken printer. (I've seen this before, too. And, hopefully, this is not the case.)

Not sure what you mean by this.

Questions
What OS is your customer running?

The IT contractor was unable to tell me. He told me that their IT managers had demanded we supply a new printer as "there was nothing wrong with their network".

Also, you mention Citrix. What exactly is your customer printing from?

They won't (yet) tell me what they are running. I am guessing that they may be running Citrix as this type of problem with printers dropping off the print subsystem seems common on Citrix systems - firstly becase Citrix seems to add another level of configuration/complexity and secondly because Citrix administrators seem unwilling (or perhaps incompetent) to investigate problems deeply. In my experience they tend to keep changing printers till they find one that luckily happens to work with their system.

Should you do capture packets, unless you have been trained on understanding printer languages, I'm not sure how that will help you...asuming you are successful.

I'm hoping to trap a text file of packets that carry the IP of this printer and see if they offer any clues about whether or not fresh data comes down to the printer when a print job is triggered. Even if I can't decipher each packet I feel I should be able to gauge roughly what is happening when.

Some of the people I have spoken to today suggest I need to use Wireshark, so I will research this further.

musher0 · #33 Post by **musher0** » Mon 14 Jan 2013, 16:06

Hello, greengeek and the bunch.

This topic was also answered, last month I believe, from the angle of compiter security, here :
http://murga-linux.com/puppy/viewtopic. ... 5&start=15

Just follow the discussion for lsof on that page.

musher0

gcmartin · #34 Post by **gcmartin** » Mon 14 Jan 2013, 18:34

greengeek wrote:
gcmartin wrote:You say you are using a cross-over cable. Why are you using a cross-over? Are you not able to use your customer's LAN?
Correct - I can not risk connecting my laptop to the customers network at this stage. (maybe later if I have their permission)
gcmartin wrote:You never mentioned if you could utilize the customer's printer from your PC. Can you print?
Yes, I can print to the customers printer from my PC (via crossover cable)
gcmartin wrote:Should you do capture packets, unless you have been trained on understanding printer languages, I'm not sure how that will help you...asuming you are successful.
I'm hoping to trap a text file of packets that carry the IP of this printer and see if they offer any clues about whether or not fresh data comes down to the printer when a print job is triggered. Even if I can't decipher each packet I feel I should be able to gauge roughly what is happening when.

Some of the people I have spoken to today suggest I need to use Wireshark, so I will research this further.

OK, here my accessment from what you share.

I am still confused when you share that you cannot connect your PC to the customer's LAN ??? But can connect your printer to his LAN. Further, when you share Wireshark and other LAN test tools how do you intend to connect for observation? Be aware, you are at a distinct disadvantage since you are not capable of using your machine that you have already tested with.

Aside from that
You do NOT have a printer problem based upon your cross-over cable work and the fact that your customer can access the new printer's webpage.

If you know a little about priner setup, you may want to follow these instructions:

Power up the old printer
Use your cross-over cable to connect to its webpage
You MAY want to test to see if you can print to it (Get back to me if you can print to it)
Write down its MAC address AND its LAN address
Power up the new printer
Use your cross-over cable to connect to its webpage
Set the new printer's MAC address AND its LAN address to match the old printer.
Connect the new printer to the LAN
Insure that your customer can connect to tts webpage
Print. (This assumes the PC's OS has the correct Printer driver.)

Lastly, you may want to change this thread's title as it appears more about Printer problem than about LAN/WAN ports

Also be aware that you could be looking at a PC printer driver problem or you "may" have some sort of a LAN security problem in play.

here to help

greengeek · #35 Post by **greengeek** » Mon 14 Jan 2013, 19:02

gcmartin wrote: Lastly, you may want to change this thread's title as it appears more about Printer problem than about LAN/WAN ports

Thanks GC, yes my questions have strayed off the original topic so I will not post further here. I will do further research about the methods (hardware and software) that will allow me to tap the cable to the printer and extract the data packets. If I have any info/clarification/solutions I will begin a new thread. Thanks all for the help.

EDIT: Just one last note:

I am still confused when you share that you cannot connect your PC to the customer's LAN ??? But can connect your printer to his LAN. Further, when you share Wireshark and other LAN test tools how do you intend to connect for observation

I think maybe I was not clear enough about the printer: It is not my printer - it is the customer's printer but they bought it (brand new) from the company I work for. I cannot connect my PC to their LAN for security reasons. However, with their future permission I should be able to connect my PC to the Rx pair in the cable to the printer (so that my PC is only "listening" to the data packets and cannot respond). Information I found on google suggests I can make a "passive network tap" which will attach to the rx wires without interrupting the connection between the printer and router. Then I will use wireshark and/or peasyscan etc to evaluate what data activity is occurring on the interface to the printer. Hopefully.

If successful I will detail this in a new thread.
.

rcrsn51 · #36 Post by **rcrsn51** » Mon 14 Jan 2013, 19:08

Here is a really simple test. Send a job to the printer and watch for the Ethernet port indicator lights to start blinking.

greengeek · #37 Post by **greengeek** » Mon 14 Jan 2013, 19:24

My understanding is that the port lights can blink for many reasons other than an incoming data packet - for example I believe routers can issue periodic automatic pings etc. I'm just hoping to be able to trap a distinguishable data packet that convinces me beyond doubt that it is actual valid data that is reaching the printer, not just a "control" packet.

On some networks I see port lights flashing very quickly - even when there is no active print job at all.

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