[Demexp-dev] Re: Issue to open an RPC TCP connection on the Internet

[David MENTRE]

Hello Gerd,

Thank you for the quick answer.

Gerd Stolpmann <address@hidden> writes:

> I would suspect this is a routing problem. ECONNREFUSED is only returned
> when a certain response arrives (I think this is an ICMP packet). It
> might be worth to check that (e.g. using tcpdump, or better, ethereal).
> That behaviour reminds me of certain (mis-configured?) routers that
> generate such packets when the route is not yet established.

Yes, good suggestion to check with Ethereal. I should have think of it.

> If it was a timeout issue, you would see ETIMEDOUT.

[ about socket option of RPC ] 
> No socket option is set.
>
>> Or would this "Connection refused" message be related to another issue?
>> Any hint?
>
> First check that there is really a listening port on the remote side.
> ECONNREFUSED primarily means that nobody is listening.

I'm sure the server is working on the remote side (it works after 2 or 3
attempts, and I can check mannually).

[ about Nagle algorithm ]
> I never used it.
>
> Usually, you have no chance to reduce the latency significantly. Many
> ISPs optimized their networks for throughput in the past (especially in
> the "last mile"). When I ping my point-to-point link, I get already a
> turnaround time of 10ms. When I ping sites in the US, I get a time of
> ~170ms. Of course, you cannot get below these values by enabling certain
> options.

You are probably right. I did not had the idea to check the number but
TCP timeout before transmitting a segment should be far below long link
latency.

Best wishes,
d.
-- 
 address@hidden