Computing desk
< April 24	<< Mar \| April \| May >>	April 26 >

Welcome to the Wikipedia Computing Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

April 25[edit]

Extending Classes in Java[edit]

Hi. I just have a quick question. If I am extending a class in java -- after I call super on it -- what happens with the instance variables of the extended class? Can I use simply their names [when calling from the lower class] (such as example) or should I use the format of (super.example)? Furthermore, how should I use its methods? Should I use (randomMethod()) or (super.randomMethod())? Thank you Sharpshot240 (talk) 04:04, 25 April 2008 (UTC)[reply]

This is largely a style question, I would go with only using super where necessary (e.g. calling an original version of a method that is reimplemented). I can't think of any reason that I would want to hide a superclass variable then access it. One thing to watch is overriding a method called in a superclass's constructor, because at the time it is called the sub class variables will not have been initialized, see [1]. -- Q Chris (talk) 07:34, 25 April 2008 (UTC)[reply]

Tracing IP address[edit]

I am trying to trace the sender of an email. I know how to get the sender's IP address through email headers, but when I run a WHOIS search on the IP address (which begins 10.*), all it tells me is that the address is owned by the Internet Assigned Numbers Authority. I was expecting more from WHOIS, like a domain name or something. Can the email header tell me any more? --Bluegrouper (talk) 08:30, 25 April 2008 (UTC)[reply]

The email headers usually feature lots of different IP addresses. Have you tried all of them? Also, so there are many "Whois" servers. I usually try ARIN, then the links to other the continental Whois services at the foot of that page, and finally Sam Spade. Remember though, if you are trying to track down someone who is sending you spam, they are unlikely to respond to your attempts to get them to stop and are more likely to add you to their "suckers list" instead. Astronaut (talk) 10:53, 25 April 2008 (UTC)[reply]

You understand that E-mail can contain forged headers, right? See E-mail and E-mail authentication for more information.

Atlant (talk) 11:36, 25 April 2008 (UTC)[reply]

Don't bother trying to track down a 10.*.*.* IP address, that's an IP in the RFC1918 address space, used on private networks (such as the user's home LAN or the sender's ISP's internal network). You want to look at the IP address of the system logged by your own ISP, because that's really the only reliable Received: header (given that you trust your own ISP). Anything else can and will be added by the sender, and is possibly forged. -- JSBillings 11:53, 25 April 2008 (UTC)[reply]

We have an article on private networks like 10.*.*.*. It is probably a step in the routing of your email that involved one server sending to another mail server internally on an internal network. Perhaps you should look at the next IP in the trail. --Spoon! (talk) 12:26, 25 April 2008 (UTC)[reply]

Thanks for the replies. Yes, I know email can contain forged headers, and no it's not spam I'm trying to trace. This tutorial suggests (point 5, three-quarters of the way down) that the sender's actual IP address will always be the in the bottommost Received: header. It also says (point 3, a little higher) that the topmost Received: header (which I'm assuming is the one JSBillings describes as "the IP address of the system logged by your own ISP" contains the IP address of the sender's email server, not the IP address of the sender himself. Given what you say above about the RFC1918 address space, is there any way I can identify the sender? --Bluegrouper (talk) 12:34, 25 April 2008 (UTC)[reply]

That page you gave is somewhat correct, but in your case, the sender's IP isn't actually helpful, because it's on a private network. You need to look at the Received: header where the ISP accepts the connection from the sender, which might be the second-to-last Received: header. Unfortunately, as with services like Google Mail, who uses a private network internally, it won't be too helpful. -- JSBillings 13:11, 25 April 2008 (UTC)[reply]

Also, the topmost Received: header isn't always going to be the point where your ISP accepted the connection from the sender's ISP. Most ISPs nowadays bounce the message around through primary MX systems, some antivirus/antispam systems and finally to mail-store systems. The tutorial you list must be somewhat dated to have such a simplistic view of mail systems. -- JSBillings 13:14, 25 April 2008 (UTC)[reply]

While whois is helpful for finding out which company owns an IP address, it is worthless for finding out the location of people using large ISPs. I prefer to use traceroute. It will break through the "it is somewhere on this continent" range and show you which routers/switches were used to get to the IP address. Those routers/switches tend to have names which identify their general location. -- kainaw ™ 16:15, 25 April 2008 (UTC)[reply]

Moniter the remote system[edit]

Hai

I need Help from You pepole.Please clear it.Mointering the Remote system through lan connection is Possible? and if it is Possible how is it? please explain me.

Because I am Adminstrator in my company.In My company many of them Open the Server And Doing Somthing so i want to watch the system at any other system is connected in lan.

Main thing The person Don't to Know if i watching my system from Remote place. So please help me as fast as.

Advance Thank You

R.Rajesh Kumar —Preceding unsigned comment added by 122.164.51.157 (talk) 12:39, 25 April 2008 (UTC)[reply]

I won't start talking about rights to privacy, but if (an example) the administrator at my workplace did this kind of monitoring, I certainly wouldn't work there.

Anyway, for Windows, you could try radmin, or VNC. Or you can use a trojan horse such as SubSeven - they work well for monitoring.

And please sign your posts with four tildes: ~~~~

--grawity 13:13, 25 April 2008 (UTC)[reply]

I think UltraVNC deserves a look. To answer Grawity, I would say I wouldn't either. I hope that my employers would trust me because if my employer did not trust me, they would probably fire me. (Dang, I am "soapboxing" again!) Kushal 01:54, 26 April 2008 (UTC)[reply]

Perhaps an alternative to the "invading employees privacy" route, would be to get a senior manager to lay down the law regarding server updates. You should at least have the backing of your managers if you took your concerns to them. I would also suggest you only grant server access to those who need it. Astronaut (talk) 10:33, 26 April 2008 (UTC)[reply]

I don't know if there is a way to have absolutely zero leakage. Stuff happens, even at top secret places like Cupertino, California. You may be able to avoid detection of instances of oversight but it is difficult to maintain complete secrecy of what you are doing. Therefore, what you asked

“

Main thing The person Don't to Know if i watching my system from Remote place.

”

does not seem to be possible. Please remember that there are other ways employees can find out that a monitoring system exists. Therefore, I would suggest you tell them about it upfront. Depending on where you live, it might be an legal battle (which, if I were you, I would want to avoid). IANAL, but please make sure you talk to your corporate lawyer AND get a second opinion from someone unrelated to your company.

Do you just want to monitor the servers in your company and not the individual workstations? If so, you should use user access control. If you are using Unix or Unix-like operating system in your servers, you can do a lot of fine tuning on which user gets what amount of access. Logging their activities should also be possible without a lot of effort. Just let the Wikipedians know that you need help with these operations. I am sure quite a few Wikipedians around here are conversant with Unix-like servers.

If this response was off-topic or unhelpful, please let me know. Kushal 21:09, 26 April 2008 (UTC)[reply]

Can you tell us more. What operating system is your server? Who is doing something with the server - your employees or hackers? And what do you want to monitor - the programs being run on the server; the network traffic; memory/hard disk usage? Also, why is it important that nobody knows you're monitoring them? --h2g2bob (talk) 21:36, 26 April 2008 (UTC)[reply]

running wengophone[edit]

trying to run wengophone on ubuntu 7.10

I unzip the tar and try to run the binary (no other makes or compiles necessary it's all standalone from what i understand) and get this:

skb@skb:~/Desktop/WengoPhone-2.1.2-minsizerel$ ./wengophone.sh exec: 20: ./qtwengophone: not found skb@skb:~/Desktop/WengoPhone-2.1.2-minsizerel$ ./qtwengophone bash: ./qtwengophone: No such file or directory

but qtwengophone is clearly evident on an ls

I've had this problem before when running the binary for X-lite softphone too. any ideas? —Preceding unsigned comment added by 71.147.37.158 (talk) 20:50, 25 April 2008 (UTC)[reply]

Photoshop[edit]

Hello all,

How can I make gradients in colours with Photoshop CS?

Thanks,

BG 7 23:38, 25 April 2008 (UTC)[reply]

With the Gradient Tool. Googling "photoshop gradient tool" turns up many helpful sites, like this one and this one. --75.36.41.18 (talk) 05:22, 26 April 2008 (UTC)[reply]

If you're just starting to learn image manipulation, I suggest learning GIMP to free you from commercial product dependency. --antilived^{T | C | G} 06:02, 26 April 2008 (UTC)[reply]

Or... if you already have Photoshop CS, you might as well learn the industry standard. (Or you could meet it half-way and try GIMPshop, but then again, you could just use what you have.) --75.36.41.18 (talk) 07:08, 26 April 2008 (UTC)[reply]

If by "have" you mean "pirated", no one would pay thousands of dollars for something they don't even know how to use. --antilived^{T | C | G} 11:40, 26 April 2008 (UTC)[reply]

Is it not possible the question asker is using a school PC, and simply expanding their horizons? Additionally, isn't there a student discount? An aspiring art student might spend the substantially more trivial cost for a student license... neither here nor there, 75.36 has addressed the question. Ironmandius (talk) 16:32, 26 April 2008 (UTC)[reply]

Or a work PC. I've never purchased Photoshop myself but I've never pirated it. --140.247.11.7 (talk) 17:12, 26 April 2008 (UTC)[reply]

reset Thanks for the help. I have photoshop in two ways. 7.0 at school, and CS at home (oh and soon CS3 on my mac!). I do know how to use photoshop, I just want to know how to do proper gradients as in the past I have just used either paintbrush to paint layers, or a rubber with transparency.

Thanks,

BG 7 16:39, 26 April 2008 (UTC)[reply]