[IPv6]: Test Server in setup more picky than reality ... [Errno 111] Failed to c

[sander]

Hi,

It looks like "Test Server" in the setup often says "[Errno 111] Failed to connect: (110, '[Errno 113] No route to host') -[email protected]:119" when the OS/telnet has no problems reaching that IPv6 NNTP server. See below

If a click Test Server a lot of times, I sometimes get the correct "Connection Successful!"

So: a intermittent problem. Quite confusing.


ubuntu@ubuntu:~$ telnet reader.ipv6.xsnews.nl nntp
Trying 2001:67c:174:101::2...
Trying 2001:67c:174:101::5...
Connected to reader.ipv6.xsnews.nl.
Escape character is '^]'.
201 reader.ipv6.xsnews.nl NNRP Service Ready (no posting).
quit
205 Transferred 60 bytes in 0 articles, 0 groups.  Disconnecting.
Connection closed by foreign host.
ubuntu@ubuntu:~$

[shypike]

What is your point exactly?
The timeout is shorter for the test button than in normal communication.
You wouldn't want to sit out the standard 2 minute timeout, would you?

[sander]

My point is that SAB's test button (often) says that a (IPv6?) newsserver is unreachable, even if that newsserver is reachable.

I'll check whether it's a timing issue...

Thanks.

[jcfp]

ubuntu@ubuntu:~$ telnet reader.ipv6.xsnews.nl nntp
Trying 2001:67c:174:101::2...
Trying 2001:67c:174:101::5...
Connected to reader.ipv6.xsnews.nl.

The problem is the hostname resolving to two ip addresses, but one of those not working. Notice how telnet tries both before it connects, sab doesn't (and shouldn't) do that and times out trying the non-working one. Seems alot of folks get hit by this since the download speeds from the working server have been truly excellent recently

[sander]

Impressive thinking! Thanks you.

Question: why should sab not try both IP addresses? Telnet does, and that seems useful to me ...

[shypike]

Because we're not aware the we can get more than one.
How do you suggest we solve this? Flip a coin?
I mean, isn't it kind of stupid to provide two IP addresses one of which isn't working?

Work-around is to use the numerical IP of the working one 

[sander]

Because we're not aware the we can get more than one.
How do you suggest we solve this? Flip a coin?
I mean, isn't it kind of stupid to provide two IP addresses one of which isn't working?

Like jcfp says: "Notice how telnet tries both before it connects". So: both. Not flip a coin.

FWIW: www.google.com / www.l.google.com resolves to three different IP addresses. Apparently normal practice to provide >1 IP addresses.


Anyway: let's stop this thread. My point is clear. Your point is clear.

[shypike]

Telnet uses a timeout of a few seconds.
SABnzbd does its best to connect to unreliable servers by being persistent.
It would take quite a while before it decides to try the other IP.

Seriously, the downloader wasn't designed to handle a situation like this.
I agree it would be an improvement if it did.
Just wondering how worthwhile this would be.
Do any of the other newreaders support this situation?
How frequently does it happen or is it just this specific xs4all servers?