Ping webserver when iphone app loads - iphone

I was wondering how I could ping a web server of mine when my application first starts. I am assuming I would do s via the appdelegate in the application? Is there any specific example I could use?

What is your problem actually? You want to know whether Internet and/or your server is available or you want to know when to ping it? If you want to know the network or host status then you can use Reachability sample app by Apple. This Rechability class is widely used.

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Prevent from specific app using internet connection

I have a client claims that my app can't connect to internet despite of he has WiFi connection and Safari application, for example, works fine. Is there any way to setup for specific app NOT to connect to the internet? I use in my app simple ASIHTTTPRequest library to make a connections. Maybe it influenced by jailbroken device? Regards!
No, there is no way to do this in via an iOS setting.
However I've had a problem like this with a client, where to Webservice the app connecting to was blocked by there firewall/proxy.
Later the black was lifted but all calls to the webservice where is cached by the proxy give really weird results.

How can I simplify addressing an iOS device using Bonjour?

I would like to make an application for iOS devices that would communicate with a special type of remote device using HTTP POST requests. The problem is that this device would actually act in the role of a client, while iOS device has to be the server accepting the requests. The next problem, host name and port has to be configured statically at the device sending the requests.
While I'm aware it's possible to give it a try using Dynamic DNS services and UPnP/IGD or NAT-PMP to overcome the problem with iOS device being behind the NAT router, I was wondering whether using Bonjour could simplify the problem in some way. I'm quite a newbie in networking so I'm looking for the direction and want to avoid research of Bonjour if it's not going to bring me anything.
Any other idea of how to solve the problem is appreciated as well.
I had a think about this. IMHO you can't guarantee you'll always be able to expose an iOS based service over a WAN (although it's possible) so this isn't practical.
The best solution I suggest is using uPNP to open the device behind a router to the outside world, then have it send an iOS push notification to the iPhone with the details (hostname, ip, port, etc).
The iPhone would then would then have to set up some kind of persistent connection with the firewalled device to receive data.
Bonjour is a good system to discover and connect to services/clients, but only on your local network. I don't think it is a good idea to try it over the internet.

Send location coordinate to another iPhone

I am trying to write an app that communicates with another app. I just want to see the other person on my map. Is this possible ? I can handle all the map details if I can get the coordinates in real time. Any advice on communicating with other iPhones would be great. I donot want to use Apple Push Notification service.
You can achieve this by having some web service running that allows the iphone to get and send information to it. Look around this site, the question of how to make requests from a service through the iphone has been asked many many times. Specifically look at NSURLRequest/NSURLMutableRequest documentation ...hope this helps
I would suggest you look into Bonjour services for the iphone. If you want one instance of your app to communicate with another instance of the same app on another iphone, then this is probably what you want, unless you want to use gamecenter.
With bonjour services you can advertise a service on the phone while the app is running and have the other iphone connect to that service and send it some data.

if I have an iphone's IP address is there anyway I can communicate with it?

are there any services running by default on an iphone that would let another ip address communicate with it if the iphone's ip is known?
Yes, technically, you can. There are a couple of issues though:
Mobile IP addresses usually change
When the phone is in sleep mode, its network interface is probably not reachable.
So I don't think you can rely on that for initiating a communication with the phone.
There aren't many options out of the box on a non jail-broken phone. However, you can write your own client application that runs on the phone. It accepts or initiates the remote connection.
And in that case, the protocol is entirely up to you.
If you jailbreak your phone, you can install the OpenSSH package and have SSH and SFTP access to your phone.
I don't know exactly what you want to do with your app, but you can consider create a thread detached from the main one (using gcd) and use it to send/receive informations from a server using JSON objects for example. Sure you can use sockets and write a client or something like that.
I suggested a new thread because you can put it running forever (on a enterprise app, I don't know if Apple will approve a thread running on an App for AppStore).
I had to develop an app with a consistent client/server relationship and it was the way I got it working.

How to write an iphone application to control a device that exposes a telnet api

I have to write an iphone application that controls a device. This device exposes a telnet based interface. The application should ideally have user access control and customizability for each user.
I was thinking of writing C++ classes that would communicate with the device using sockets. This functionality can then be exposed through web-services that can be called by the iphone application.
However as i looked into it deeper, the api allows you to register for events using telnet and then you can receive notification when those events occur. That kinda put a spanner in the works for me. I for one dont know a "push" scenario can work with webservices.
First off i have never programmed for the iphone so far. So i am not really sure what can be done. So i was thinking if instead of having a webserver to go through, why not have the application independently running on the iphone, directly communicating with the device using sockets. The question though is, is that possible and second i am thinking it would raise a security aspect. First we could control security as everything was going through our central server. Is there a way to handle security (in the sense who has access to the device) without having a central server.
I am sorry that this seems like an unorganized post, but iam trying to brainstorm here.
Looking forward to hear your opinions.
Look up the NSPort and NSStream classes.
I'm looking to do this same thing. Have a program running on one computer and want to send/receive telnet commands from iOS. Built one for Android using the Commons library- which has a telnet client API, but don't know the best way to do it in Objective-C (without writing a telnet client library).
As a start, however, I found the OFC library on Google Code. Looks like something of a Commons-like feel, and there seems to be a telnet client. You might take a look at that.