[rabbitmq-discuss] More about SSL_TIMEOUT

Mon Jun 9 17:15:29 BST 2014

[Michael Klishin suggested me to post the issue in a new thread in order 
for it to be reviewed properly for possible inclusion in your issue tracker]

So to remind. the issue is Rabbit MQ Java client failing to connect to 
the server (with "connection reset").
The problem is there because Rabbit MQ server kills inbound connection 
should SSL handshake not finish in 5 seconds.
I first experienced the issue in the network where something was not 
quite right with DNS server - I found that when establishing SSL 
connection the Java client did a reverse lookup of IP address. (That 
means the "forward" DNS lookup was already done and IP address resolved 
from the server name, TCP connection was already established to that IP 
and only then Java SSL code started reverse lookup).
When that reverse DNS lookup takes more than 5 sec, Rabbit MQ server 
kills the connection. And even though we retry 30 seconds later - it is 
not going to improve so process repeats.

Since that first time, I saw this problem multiple times on other 
networks. The solution each time was to manually hack /etc/hosts file to 
put there the IP address with arbitrary name. This makes that IP to name 
translation quick and connection succeeds. This is obviously a 
workaround, not a solution.

IIRC, that reverse lookup was done by standard Java SSL support, not 
Rabbit MQ client library so it is not a Rabbit MQ bug technically. I do 
not know why Java SSL code does that lookup but it did not seem easy how 
to avoid it.

So for me the solution would be to increase the timeout to 10 sec 
minimum or, probably better, make it configurable.

Many thanks

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