NSURLRequest, why does craigslist return a 404?

Question

Hi there, I'm building my first iPhone app and I'm stymied.

I'm trying to build an RSS reader, and I'm trying to use a feed from craigslist. This code, using stackoverflow, returns "Status code: 200":

- (void)parseRSSFeed:(NSString *)feed withDelegate:(id)delegate
{
 responseData = [[NSMutableData data] retain];
 feed = @"http://stackoverflow.com";
 NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:feed]];
 [[NSURLConnection alloc] initWithRequest:request delegate:self]; 
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
 NSLog(@"status code: %d", [((NSHTTPURLResponse*) response) statusCode]);
 [responseData setLength:0];
}

All is well. But if I change feed to, say, "http://portland.craigslist.org/muc/", I get a status code of 404.

Is there anything I'm missing? Does Craigslist disallow iPhone access to its website? Is there some escaping I need to do on the URL?

The code, with the craigslist URL, is here. This is exactly as I'm using it, and it returns a 404:

- (void)parseRSSFeed:(NSString *)feed withDelegate:(id)delegate
{
 responseData = [[NSMutableData data] retain];
 feed = @"http://portland.craigslist.org/muc/";
 NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:feed]];
 [[NSURLConnection alloc] initWithRequest:request delegate:self]; 
}