port closed / traders den issue

Ask for help and report issues not specific to either the Mac OS X or GTK+ versions of Transmission
udo
Posts: 18
Joined: Mon Oct 01, 2012 11:24 am

port closed / traders den issue

Post by udo »

Hello,

I am running Fedora Linux with iptables firewalls.
Despite the port being open, as confirmed by external port check sites, transmission thinks the port (6881) is closed when I test the port.
How can I find out what happens and why transmission thinks the port is closed?
I did not yet find methods to see low level logging so i used strace and wireshark to get a clue of what's going on.

Furthermore transmission cannot connect to the tracker of the tradersden. I can surf there without issue but transmission says it cannot connect.
Also here I did not find a way to get lowlevel logging so also here i used strace and wireshark to get a clue of what's going on.
Nothing yet.

What steps can I take to solve these issues?
x190
Posts: 5094
Joined: Sun Nov 30, 2008 4:59 am

Re: port closed / traders den issue

Post by x190 »

Despite the port being open, as confirmed by external port check sites, transmission thinks the port (6881) is closed when I test the port.
How can I find out what happens and why transmission thinks the port is closed?
I wouldn't worry about this. Transmission doesn't always get it right. Regarding the tracker: perhaps they are temporarily down? Perhaps you could inquire at their site. Check that your version of T is whitelisted. Are you blocking their port in iptables?
The stone age didn’t end because we ran out of stones.
---The Great Disruption - by Paul Gilding
https://paulgilding.com/
-------------------------------------------------
udo
Posts: 18
Joined: Mon Oct 01, 2012 11:24 am

Re: port closed / traders den issue

Post by udo »

I am not blocking anything w.r.t. tradersden.
The tracker appears to be working for other people.
I am now running transmission 2.71, had a slightly lower Fedora-released version before. Same issues.
udo
Posts: 18
Joined: Mon Oct 01, 2012 11:24 am

Re: port closed / traders den issue

Post by udo »

BTW: Main difference: tradersden is a tcp-based tracker, the others appear to be (mostly if not all) udp.
x190
Posts: 5094
Joined: Sun Nov 30, 2008 4:59 am

Re: port closed / traders den issue

Post by x190 »

udo wrote:BTW: Main difference: tradersden is a tcp-based tracker, the others appear to be (mostly if not all) udp.
libcurl up-to-date? Check your log messages.

https://trac.transmissionbt.com/wiki/EditConfigFiles

message-level: Number (0 = None, 1 = Error, 2 = Info, 3 = Debug, default = 2) Set verbosity of transmission messages.
The stone age didn’t end because we ran out of stones.
---The Great Disruption - by Paul Gilding
https://paulgilding.com/
-------------------------------------------------
udo
Posts: 18
Joined: Mon Oct 01, 2012 11:24 am

Re: port closed / traders den issue

Post by udo »

The debug log doesn't tell me anything more than: Could not connect to tracker.
No lower level mentions of what was tried and how it failed. :-(

I am running Fedora 17 -updated almost daily- so I guess libcurl is up to date: libcurl-7.24.0-5.fc17.x86_64
I built transmission 2.71 from source as the repo's did not have this version yet so the code did not complain when built.
x190
Posts: 5094
Joined: Sun Nov 30, 2008 4:59 am

Re: port closed / traders den issue

Post by x190 »

https://trac.transmissionbt.com/wiki/En ... tVariables

If TR_CURL_VERBOSE is set, debugging information for libcurl will be enabled. More information about libcurl's debugging mode is available here.
The stone age didn’t end because we ran out of stones.
---The Great Disruption - by Paul Gilding
https://paulgilding.com/
-------------------------------------------------
udo
Posts: 18
Joined: Mon Oct 01, 2012 11:24 am

Re: port closed / traders den issue

Post by udo »

Now that is an interesting setting!

I now see stuff like:

Code: Select all

* About to connect() to www.tracker.example.com port 80 (#1)
*   Trying 199.101.99.188...
* Name '<my local ipv6 address>' family 2 resolved to '<my local ipv6 address>' family 10
* bind failed with errno 22: Invalid argument
* Closing connection #1
I see confusion about the adresses family.
The <my local ipv6 address> address is in settings.json for "bind-address-ipv6".

When I set "bind-address-ipv6" to :: stuff starts to work again for thetradersden.
Also the TCP port is now open.
I officially declare this a bug.
udo
Posts: 18
Joined: Mon Oct 01, 2012 11:24 am

Re: port closed / traders den issue

Post by udo »

I initiated another trac ticket, referring to this thread. (old attempts are numbered 5065 and 5066)

I am quite sure the torrent is valid as with "bind-address-ipv6" set to :: all works as expected.

Additional info:
It doesn't matter whether "bind-address-ipv6" is set to the automagically configured ipv6 address or via IPV6ADDR_SECONDARIES with RFC 3484 support, the result is the same:
No working ipv4 tcp connections to tracker, no good tcp port test.
Last edited by udo on Wed Oct 03, 2012 8:16 am, edited 1 time in total.
x190
Posts: 5094
Joined: Sun Nov 30, 2008 4:59 am

Re: port closed / traders den issue

Post by x190 »

I officially declare this a bug.
Well...

https://trac.transmissionbt.com/wiki/EditConfigFiles

bind-address-ipv6: String (default = "::") Where to listen for peer connections

I suppose. Quite likely there's already a ticket for it, if you searched hard enough. Or you could re-open your ticket as this shouldn't affect tracker connections, should it???
The stone age didn’t end because we ran out of stones.
---The Great Disruption - by Paul Gilding
https://paulgilding.com/
-------------------------------------------------
udo
Posts: 18
Joined: Mon Oct 01, 2012 11:24 am

Re: port closed / traders den issue

Post by udo »

x190 wrote:bind-address-ipv6: String (default = "::") Where to listen for peer connections
This is for ipv6.
I see ipv4 problems correlated and very probably caused by this.
The ipv6 setting you mention is there to select another ipv6 address than the default, e.g. for some privacy.
bind-address-ipv4 is set to 0.0.0.0, the default.

I'll see what I can find in trac.
udo
Posts: 18
Joined: Mon Oct 01, 2012 11:24 am

Re: port closed / traders den issue

Post by udo »

https://trac.transmissionbt.com/ticket/4957 is closed, mentions the same ipv6 address, comment 9:

sorry, i didn't know that feature request. but i do think connection to ipv4 tracker should not fail silently.

https://trac.transmissionbt.com/ticket/4327 is funny: listening at ::1 makes it no longer able to connect to trackers. See comment 12 there.
udo
Posts: 18
Joined: Mon Oct 01, 2012 11:24 am

Re: port closed / traders den issue

Post by udo »

So this issue has been more or less known for over a year. (!)
Now where in the code should I look for cooking up a fix?
x190
Posts: 5094
Joined: Sun Nov 30, 2008 4:59 am

Re: port closed / traders den issue

Post by x190 »

Now where in the code should I look for cooking up a fix?
The original developer of IPv6 support doesn't seem to be active in the project anymore, so I guess you would have to just search terms like "ipv6", "bind", "::", "trackers", and so on. Painful, I know, but that's how I do it.
The stone age didn’t end because we ran out of stones.
---The Great Disruption - by Paul Gilding
https://paulgilding.com/
-------------------------------------------------
udo
Posts: 18
Joined: Mon Oct 01, 2012 11:24 am

Re: port closed / traders den issue

Post by udo »

Well, binding the ipv6 works fine.
It's some weird logic I suppose that makes it interfere with outgoing ipv4 communications.
It's the internal administration that makes it confused about ipv4 due to an explicit ipv6 number instead of a default one.
Nothing ipv6-specific.
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