[rhelv6-list] connection problem : work fine thru SSH tunnel, but not directly

[vu Pham]

On 04/23/2013 01:07 PM, Kinzel, David wrote:
>> I experience connection problem between a client app to a remote app on
>> this particular RHEL 6.4 server. ( The client  work fine with the remote
>> app on *other* RHEL servers ). The connection is made just fine, but
>> when I access the data, the client app quickly hangs up on me after
>> spitting out some data. Turning off iptables does not help, although I
>> should not try that because the connection can be made, and I could get
>> some data.
>>
>> The connections to this server will work just fine if they are made thru
>> local port forwarding via SSH.
>>
>> Initially I wanted to post onto the application forum, but because the
>> connections work thru the SSH tunnel so I changed my mind and posted
>> here. I may be wrong, as I often am. If so, I am sorry.
>>
>> Does anybody experience something similar ?
>
> Bad and strange things like this can happen if you have your MTU misconfigured.

David,

Thanks for your reply.

The MTU on all the servers are 1500. And just this application has 
problems. I tried some different values for MTU such as 1492 and 500 
last night, but it did not help.

I also wrote a test application that simulates the real client 
application's reading data section and the test app can connect to the 
server and extract data just fine. Of course, simulation of just one 
tiny part cannot draw the conclusion for the whole thing, but the result 
makes the puzzle more "puzzled" :)

Thanks,
Vu