在连接（到FTP，首先没有SSL）时，我运行：
NSArray *objects = [NSArray arrayWithObjects:@"proxy.ip", [NSNumber numberWithInt:1080], NSStreamSOCKSProxyVersion5, @"user", @"pass", nil];
NSArray *keys = [NSArray arrayWithObjects:NSStreamSOCKSProxyHostKey, NSStreamSOCKSProxyPortKey, NSStreamSOCKSProxyVersionKey, NSStreamSOCKSProxyUserKey, NSStreamSOCKSProxyPasswordKey, nil];
NSDictionary *proxyDictionary = [NSDictionary dictionaryWithObjects:objects forKeys:keys];
[iStream retain];
[iStream setDelegate:self];
[iStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[iStream setProperty:proxyDictionary forKey:NSStreamSOCKSProxyConfigurationKey];
[iStream open];
同样适用于iStream。这允许我通过socks5代理成功连接。 如果我继续没有setProperty：proxyDictionary ...（socks5禁用）我会告诉服务器切换到SSL，然后成功将这些设置应用到输入/输出流，从而给我一个SSL连接：
NSMutableDictionary *settings = [NSMutableDictionary dictionaryWithCapacity:1];
[settings setObject:(NSString *)NSStreamSocketSecurityLevelTLSv1 forKey:(NSString *)kCFStreamSSLLevel];
// to allow selfsigned certificates:
[settings setObject:[NSNumber numberWithBool:YES] forKey:(NSString *)kCFStreamSSLAllowsAnyRoot];
[iStream retain];
[iStream setDelegate:self];
[iStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
CFReadStreamSetProperty((CFReadStreamRef)iStream, kCFStreamPropertySSLSettings, (CFTypeRef)settings);
//[iStream setProperty:NSStreamSocketSecurityLevelTLSv1 forKey:NSStreamSocketSecurityLevelKey]; <-- needs to be default or unset, then it works.
对于oStream也一样。如果我禁用socks5，所有这些都可以正常工作。如果我将其打开（第一个snippit中的第7行），则在应用SSL设置时会失去联系。
如果我不得不猜测，我认为在应用（ssl）“设置”时会失去一些属性？
请帮助：）