10 Amazing iPhone 4 Features

1. 5-megapixel camera to capture high quality pictures. It also has built-in LED flash that allows to capture pictures where there is dim light or in low illumination areas. The camera has 5X zoom capability. Screen tapping allows to focus on the area you seem more important.

2. Video calling from iPhone 4 to iPhone 4 over Wireless Networks (Wi-Fi). This feature, called FaceTime, allows you and your call receiver to see the faces of each other.

3. Very high resolution phone screen with 4 times pixels as compared to previous iPhones. This feature, called Retina Display, makes text look much sharper and vibrant.

4. The phone screen is stronger and is very scratch resistant.

5. Two cameras: One in the front for video calling, and one in the back that allows to share, what is happening behind the back camera, with your call receiver.

6. IPS technology (in-plane switching) that allows clear and better screens when looking at different angles.

7. Multitasking allows you to use several applications simultaneously. You can switch from one application to another, and vice versa. For example, you can use GPS, listen to your favorite audio, get calls while running some other applications at the same time.

8. You can shoot high-defintion (HD) video wherever you go, and whenever you want. Screen tapping allows to brighten the part you want to focus on. You can also edit your videos the way you want.

9. Application iMovie allows to turn your videos into a movie.

10. Applications to share your photos and videos via MMS, or through emails, or over Internet.

More information can be found at:


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Mozilla Firefox Does Not Connect To Internet When Network Connection Is Up

This issue may happen, if you stop managing your network connections through NetworkManager. However, your Mozilla FireFox setting may be dependent upon NetworkManager service. Just to give more insight, first I will describe why this issue was happening on my system. I am using Fedora 12 distribution, and have been using NetworkManager for connection management. However, recently, to setup bridge networking for configuring virtual machines (VM) with KVM and QEMU, I had to setup a bridge interface manually (by editing /etc/sysconfig/network-scripts/ifcfg-br0), as NetworkManager does not support it yet. Due to this, I was starting/stopping network manually too as follows:

service network restart

Or if you are not root user, you must have “sudo” permission, and run:

sudo service network restart

However, with this, although network connections were up, Mozilla Firefox was working in offline mode, and was not able to connect to the Internet.

There are 2 methods by which you can solve this issue:

1. Stop NetworkManager service as follows:

service NetworkManager stop

Or if you are not root user, you must have “sudo” permission, and run:

sudo service NetworkManager stop

Note: you do not need to uninstall NetworkManager for this.

2. In address bar of Mozilla Firefox, type “about:config” (without quotes). It will show several variables associated with it. Then, in the “Filter” bar, type “networkmanager“, it should show “toolkit.networkmanager.disable“. Currently it’s value should be set to “false“. Just double-click on the value and it will switch to “true“, something you need. Specifically, after setting this variable to true, Mozilla FireFox does not depend upon NetworkManager for its connectivity.
The above solution may not work in every scenario, as the above issue is just one of the many issues causing Mozilla FireFox to not connect with Internet. To address other issues, you may go through:


Or for list of articles, you can have a look at:


Or you can also ask a question:


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F2 VISA questions asked during interview at USA (United States of America) Embassy or Consulate

These questions have been prepared by collecting information from several friends and also by searching on various sites and forums on Internet. In general, I have heard from my friends that F2 VISA interview process is not difficult and not many questions are asked from F2 visa applicants.  So these questions are just for good preparation and building self-confidence.  If some question is not clear, or you want a suggestion for answers for any questions, please leave a comment, I will try my best to give you “just a suggestion”.

General questions:
Q. What is your name?
Q. What Visa are you applying for?
Q. What is the name of your spouse?
Q. What does your spouse do in USA?
Q. Can I see your spouse’s passport/visa/I-20?
Q. When are you planning to go to USA? Have you made any specific travel arrangements?

Marriage related questions:
Q. When did you get married?
Q. Was it arrange marriage? How did you both meet? Did you know your spouse before marriage?
Q. Do you have your marriage album/photos?
Q. Can I see your marriage certificate?
Q. Have you brought the invitation cards with you?
Q. Why did you not go with your spouse (in case your husband leaves before you)?

Your spouse’s study/work/finance related questions:
Q. What’s your spouse majoring in? What’s his/her research area? What’s the topic of his/her research?
Q. When is your spouse planning to finish his studies? At which stage is he now?
Q. What would your spouse do after finishing his studies?
Q. Where did your spouse work, in India or in USA?
Q. Why did your spouse leave his/her job?
Q. (if you say, your spouse wants to come back to India) Why doesnt your spouse want to work in USA? Would he/she not work there? He/she can continue his research / work there; why does she/he want to come back to India?
Q. What did your spouse study in India? Where (which school/univ) did your spouse do his undergraduation/graduation in India?
Q. How would you fund yourself there? Who would bear your expenses there? Is your husband going to bear your expenses there?
Q. Do you have financial documents? Have you brought your spouse’s bank statements or any other supporting documents?

Your study and work related questions:
Q. What are you studying? Have you finished your studies? Are you done now?
Q. Do you plan on studying in USA? if you answers “NO” then the visa office may ask: Why not?
Q. Do you want to work there? (you can not work on F2 visa)
Q. Did you work in India?
Q. Why not? You have good education and can get good job; why do you not want to work?
Q. How would you spend your time there?

Your parents/in-laws/siblings/relatives related questions:
Q. What do your parents-in-law do in India?
Q: if your parents-in-law are in business, what kind of business?
Q: If your father-in-law is in business, the visa office may ask that who would take care of the business as your husband (if only one son) is in USA?
Q. Does your spouse have any siblings in USA? what do they do? Where do they live/ work in USA?
Q: Do they have Green Card? What kind of Visa do they have? if married, what do their spouses do?
Q: Do they want to come to India?
Q. Do you have any of your relative in US?
Q. Do you have any brothers/sisters? What do they do? Are they planning to go to US?
Q. What do your parents do?

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F2 VISA (F1 Dependent VISA) Requirements and Documents for USA (United States of America) Embassy or Consulate

The most important requirement for obtaining a F2 visa is that the individuals who are planning to visit USA (United States of America) should be a dependant of F1 visa holders. F1 dependants eligible for F2 visa are spouse and children.

In addition to this requirement, another very important thing to not about F2 visa is that F2 visa holders are not allowed to work in any form in USA. F2 visa is not a work permit and the person holding F2 visa can not indulge in any work in which that person gets paid.

F2 visa holders are not eligible to get SSN (social security number). Few years before, I think that F2 visa holders were eligible for getting SSN but were not eligible to work, as F2 visa can not be used as work permit. It seems that some F2 visa holders used their SSN to work illegally. So to prevent this to happen, now all dependants visas (like F2 or H4) where one is not eligible to work, are not granted SSN but just ITIN ((an identification number used in USA for tax purposes)) . These are just  my thoughts and I have not verified any of this.

Anyway, F2 visa holders can get ITIN number. When F1 visa holder files tax return, he/she can show F2 visa holders as dependent using this ITIN number and can get dependant’s benefits such as higher standard deductions on taxes.

Therefore, a person applying for F2 visa should keep above points in mind. Now I will list the documents required at the time of visa interview for F2.

Mandatory documents:
1. Applicant’s passport.
2. DS-160 application confirmation letter with CEAC bar code.
3. Applicant’s visa photos as specified on here.
4. Original HDFC bank visa fee receipt with two bar code stickers.
5. Interview appointment letter.
6. Applicant’s I-20 (original) (your spouse must have got this from his/her university, and sent to you).
7. Photocopy of your spouse’s I-20 document.

Not mandatory, but must-have (highly important) documents:
1. Original marriage registration certificate.
2. Wedding photo album.
3. A few Invitation cards (original).
4. Your spouse’s US bank statements (to show that he/she can finance you).
5. Photocopy of your spouse’s passport.
6. Photocopy of your spouse’s US Visa.
7. Photocopy of your spouse’s I-94 card.
8. Photocopy of your spouse’s Federal Income Tax returns
9. Photocopy of your spouse’s State Income Tax returns
10. Photocopies of your spouse’s paystubs

If your spouse (F1) is working on OPT (optional practical training), then must-have (highly important) documents:
1. Photocopies of your spouse’s (F1’s) current and previous OPT cards (employment authorization cards).
2. Photocopies of your spouse’s (F1’s) paystubs (or salary slips) for almost 1 year (although paystubs of previous few months are also fine)
3. Original and photocopy of employment letter

Supporting documents:
1. Your spouse’s Indian bank statements.
2. Applicant’s mark-sheets and certificates starting from 10th standard.
3. Applicant’s birth certificate.
4. Applicant’s Itinerary details.

Important photocopies to keep with you:
1. Photocopy of applicant’s I-20 form.
2. Photocopies of applicant’s passport’s first page, address page, and last page.

In general, it is good to have at least 2 photocopies of each original document you are carrying with you. One set of photocopies you can carry with you, and another set of photocopies you can leave at home to have backup in case something is lost.

Documents not really needed but you may have:
1. Photocopy of your spouse’s social security card.
2. Photocopy of your spouse’s car title.
3. Photocopy of your spouse’s driving license.

Note: In the above, “Applicant” means person applying for F2 visa, and “your spouse” means applicant’s spouse.

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Openswan Software As A VPN Client For Connecting To Cisco VPN Servers

I have been using “vpnc” software as a VPN client for connecting to my company’s VPN servers for quite some time. However, “vpnc” is very limited in features as it only supports IPsec aggressive mode, pre shared key (PSK) authentication, and only IKEv1 (IKE version 1). Although, “vpnc” also supports “hybrid” authentication, this hybrid authentication just involves verifying server’s certificate, but not client’s certificates. These features are just a subset of features included in various IPsec and IKE protocols. In addition to the features what “vpnc” offers, IPsec and IKE protocol suites involve IKEv1 main mode (phase 1 exchange in addition to phase 2 quick mode exchange), certificates and raw RSA keys based authentication, and IKEv2 (IKE version 2) among several others features. Due to this, I planned to move to another IPsec based VPN software that implements a large IPsec and IKE feature set. Openswan (http://www.openswan.org/) is one such popular open source (free) software available that can be used for connecting to Cisco VPN servers. Here I will explain the instruction I used for connecting to my company’s Cisco VPN server. I used the latest Openswan version (2.6.25) as of now that can be downloaded from http://www.openswan.org/download/openswan-2.6.25.tar.gz . I have experimented Openswan on Fedora and Ubuntu Linux distributions. Fedora offers pre compiled rpms, whereas it should be compiled from source on Ubuntu. For example, Openswan rpms for Fedora 12 can be downloaded from http://koji.fedoraproject.org . Various instructions for using Openswan are described next.

Installation On Fedora 12:

yum install openswan (as a root user)


sudo yum install openswan (as a non root user with sudo permissions)

Compilation and Installation on Ubuntu:

tar -xvzf openswan-2.6.25.tar.gz
cd openswan-2.6.25
make programs install

Editing /etc/ipsec.conf file:

Your ipsec.conf file should look like below:

config setup

conn   mycompany
leftid=@your company group name

leftxauthusername=your login name in your company
right=your company’s gateway IP address or host name

ike=<described in detail below>
esp=<described in detail below>

The value of “ike” and “esp” can be in the format “encryption algorithm-hash algorithm;Diffie Hellman group”, where encryption algorithm can be one of “3des” or “aes”, hash algorithm can be one of “md5” or “sha1”, and Diffie Hellman group can be “modp1024” (similar to diffie hellman group 2 or dh2) or “modp1536” (similar to diffie hellman group 5 or dh5). Although, there are several others encryption algorithm and Diffie Hellman groups implemented in Openswan, however, the values described here are the most frequently used. For example, different values of “ike” can be as follows:

ike=aes-sha1;modp1536 or ike=aes-sha1
(by default, Openswan assumes “modp1536”, so it is not required to be written explicitly)

“esp” can also take values similar to “ike” as follows:


The values of “ike” describes the IKE phase1 (main mode or aggressive mode) “encryption algorithm-hash algorithm;Diffie Hellman group” combinations, whereas “esp” describes IKE phase2 (quick mode) “encryption algorithm-hash algorithm;Diffie Hellman group” combinations. You must contact your company’s network administrator about the exact configured values for these parameters.

A sample /etc/ipsec.conf will look like below:

config setup

conn   mycompany

Note: Please leave a space or tab before each line in /etc/ipsec.conf, except the lines “conn setup” and “conn mycompany”.

Editing /etc/ipsec.secrets:

<your company group name as the value of “leftid”>: PSK “your company’s group password”
<@username similar to leftxauthusername beginning with @> : XAUTH “your user password”

A sample /etc/ipsec.secrets will look like below:

@cisco-group: PSK “abcd1234”
@johnmatt : XAUTH “xyz12wx”

Starting Openswan:

service ipsec start (must be root)


sudo service ipsec start (as non root user with sudo permissions)

Establishing VPN Connection:

ipsec auto –up mycompany (must be root)


sudo ipsec auto –up mycompany (as non root user with sudo permissions)

If you see “IPsec SA established” as one of its output, that means that the connection is established.

Stopping Openswan:

service ipsec stop (must be root)


sudo service ipsec stop (as non root user with sudo permissions)

Configuring Aggressive Mode:

By default, Openswan uses IKE “main mode” during its phase1. However, it is possible that your company’s Cisco VPN server may be using “aggressive mode” instead of “main mode”. For configuring, “aggressive mode”, add following line anywhere in the “conn mycompany” section.


Perfect Forward Secrecy (PFS):

By default PFS is enabled in Openswan, to disable that add following line anywhere in the “conn mycompany” section.

pfs=no (pfs=yes by default)

Configuring Openswan With RSA Secure ID (One Time Password (OTP)):

In the above instructions, I have assumed that your user password (@johnmatt : XAUTH “xyz12wx”) does not change, and remains same for long duration. However, several companies are giving RSA secure IDs (also called RSA tokens) that are being used as one time password (OTP) for better security. If you have also got RSA secure ID from your company, then you need to change your /etc/ipsec.secrets slightly, and your /etc/ipsec.secrets will look as follows:

@cisco-group: PSK “abcd1234”

Notice that there is no XAUTH line now. The reason is that when you will run “ipsec auto –up mycompany” command, it will prompt you for user password. When using RSA secure IDs, your password generally would be “PIN+RSA number displayed”, where PIN is a fixed secure string created by you. Your company must tell you about it, so you should not be worried.

In general, Openswan offers many more configuration options than those described here. Please run commands “man ipsec.conf” and “man ipsec.secrets” for more details. If you need further guidance on Openswan configuration, please leave a comment.

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How To Connect Securely With Your Company's VPN server (Cisco VPN servers) Using "vpnc" Client

Now days, several software companies provide their employees with the flexibility of working from home as and when there is a need. This way, employees can maintain a better balance between their work life and personal life. However, while working from home, employees are needed to use a VPN (virtual private network) client for connecting with their company’s VPN servers. VPNs are useful for preventing company’s confidential communication from outsiders. “vpnc” is a software, that can be used to accomplish this, and can be downloaded from http://www.unix-ag.uni-kl.de/~massar/vpnc/. I am assuming that your company uses Cisco VPN servers, because “vpnc” is primary developed as a client for them. “vpnc” software implements IPsec (IP Security) based technology for providing VPN connections. The instructions, I am going to describe below, have been tested on Linux (Ubuntu and Fedora) machines. On Fedora, you can do “yum install vpnc”, and on Ubuntu, you can do “apt-get install vpnc” for installing “vpnc” on your machine, if you do not want to compile from “vpnc” source code. You must be logged in as a “root” user for installing software on your Linux machine. If you are not logged in as a root user, then you must have “sudo” permission to install “vpnc” software, and then commands will be “sudo yum install vpnc” on Fedora, and “sudo apt-get install vpnc” on Ubuntu.

Simple “vpnc” configurations (mostly used):

First, you need to create a file named as “vpnc.conf” in your “/etc” directory. Again, for creating files in /etc directory, either you must be root user or must have “sudo” permissions. The contents of your “vpnc.conf” file should be:

IPSec gateway (you can ask your company’s network administrator about it).
IPSec ID (Again, you can ask your company’s network administrator about it).
IPSec secret (Please ask your company’s network administrator about it, and should be kept secret).
Xauth username (You must be knowing this).
Xauth password (You must be knowing this).
NAT Traversal Mode natt

A sample vpnc.conf file should be as follows:

IPSec gateway your.vpn.server.com
IPSec ID  abcdef
IPSec secret xyz1234
Xauth username johnmatt
Xauth password at!23gh5
NAT Traversal Mode natt

Once you have written above information in your vpnc.conf, then type following command on the command prompt:

vpnc (if logged in as a root)


sudo vpnc (if not a root user)

In the above instructions, I have assumed that your user password (Xauth password) does not change, and remains same for long duration. However, several companies are giving RSA secure IDs (also called RSA tokens) that are being used as one time password (OTP) for better security. If you have also got RSA secure ID from your company, then you need to change your vpnc.conf slightly as discussed next.

vpnc with RSA secure IDs:

Then, your vpnc.conf should like:

IPSec gateway your.vpn.server.com
IPSec ID  abcdef
IPSec secret xyz1234
Xauth username johnmatt
NAT Traversal Mode natt

Note, the line “Xauth password at!23gh5” is missing. The reason is that now vpnc will prompt you for a password. When using RSA secure IDs, your password generally would be “PIN+RSA number displayed”, where PIN is a fixed secure string created by you. Your company must tell you about it, so you should not be worried.

Advanced “vpnc” configurations:

By default, vpnc is configured with Diffie Hellman group 2. If your company’s VPN server is configured with some other group, then you need to enable following option in your vpnc.conf file:

IKE DH Group <dh1/dh2/dh5>

If your company’s VPN server is configured with PFS (Perfect Forward Secrecy), then enable following option in your vpnc.conf (by default disabled):

Perfect Forward Secrecy <nopfs/dh1/dh2/dh5/server>

By default, vpnc uses IPsec in PSK (pre shared key) mode for authentication. However, if you want to use certificates for authentication, you also need to use following configuration variables in your vpnc.conf:

IKE Authmode hybrid
CA-File  <certificate-authority-pem-file>
CA-Dir <path-to-your-certificate-authority-directory>

When running vpnc, it does not output any messages. However, if you want to see the output messages for debugging purposes, please enable the following option in your vpnc.conf file.

Debug <0/1/2/3/99>

Insecure vpnc options:

I would suggest vpnc users never enable following options in your vpnc.conf.

Enable Single DES

If you enabled single DES (Data Encryption Standard), your VPN connection will become a joke. Also, be careful while enabling following:

Enable no encryption

If you are sure that you are not communicating any confidential or sensitive company information, or you may be concerned with your VPN connection’s performance that may have been slowed down due to encryption, you may enable this option. In general, DO NOT enable this option.

Note: please refer vpnc man page (command: man vpnc) for more details on configurations.

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H4 VISA Documents Required At Port Of Entry In USA (United State of America)

1. Copy or Original I797A (I129 type)
2. Passport (with H4 visa)

It is good to have other documents that you carried with you during your H4 visa interview, as specified here:

Questions asked:
1. Where does your spouse work?
2. What is your spouse’s job description?

In addition, it is better to prepare other questions like here:

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