I wrote a monitoring app that boots an ec2 instance and then starts a minecraft server on that instance. While everything is starting up, about every 3 seconds, the app submits a status query to get the server's state and the number of players logged in. When I attempt to log in with my minecraft client, I get the "end of stream" message. This happens consistently. If I start the server WITHOUT sending the query request, everything starts normally. This happens even if I send the status query ONLY ONCE, so it's not that the server thinks I'm spamming it. Below is the python code I'm using to send the status query (from Will Nowak <wan@ccs.neu.edu>).

def GetMCStatus(hostname, port=25565, timeout=0.5):
"""Query a minecraft beta server.

Args:
hostname: (String) hostname of the server to connect to
port: (integer) port number to connect to
timeout: (float) timeout in seconds for making a TCP connection

Returns:
list: If successful, something like:
[True, 'MOTD here', 5, 20] # Online, MOTD, cur_players, max_players
If unsuccessful, returns [False]
"""
logging.debug('Trying to establish connection to %s:%d with timeout %f',
hostname, port, timeout)
try:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
ip = socket.gethostbyname(hostname)
s.connect((ip, port))
s.settimeout(timeout)
s.send(chr(254))
data, _ = s.recvfrom(2048)
if data and data[0] == chr(255):
data, _ = codecs.utf_16_be_decode(data[1:])
data = data[1:]
p = data.split(u'\xa7')
return [True] + p
except socket.error:
logging.exception('Socket error when querying from %s', hostname)
return [False]