Question

I’m working on an iPhone app that requires a basic client/server interaction model. For this I am going to use Bonjour and NSNetService, along with NSNetServiceBrowser to discover others on the same network. I have followed several different guides which more or less have the same sample code.

Relevant Server Code

...
serverName = [[UIDevice currentDevice] name];
netService = [[NSNetService alloc] initWithDomain:@"local."
                                             type:@"_myservice._tcp."
                                             name:serverName
                                             port:port];
...

The service publishes successfully, i.e. I get the netServiceDidPublish: callback

Relevant Browser Code

...
browser = [[NSNetServiceBrowser alloc] init];
[browser setDelegate:delegate];
[browser searchForServicesOfType:@"_myservice._tcp." 
                        inDomain:@"local."];
...

Now the result of all this is interesting:

1. Running on an iPhone, the device can only see its own published NSNetService.
2. Running on 2 iPhones, neither device can see the other’s NSNetService.
3. Running on the iPhone Simulator, it will find all NSNetServices, including its own.

Screenshot of iPhone Simulator

I’m sort of at a loss here… The simulator is working exactly as expected. However on the device it is not, I cannot get 2 different iPhones on the same WiFi to see each other, they only see themselves. Any idea what is going on here?

Answer 1

Turns out that the router that I’m on had an “SPI Firewall” enabled by default. Turning this off solved the problem.

One thing that I’m still curious about is: How come the requests coming from my Mac, both the iPhone Simulator and a Bonjour Browser, were able to get through this firewall but 3 different iPhones were not?