[Android] Failure to connect to Calibre

[tamhas]

After many months of having no problem at all, when I try today to connect Calibre Companion to Calibre via wireless, I get a failure to connect. I went into change IP, although nothing has changed, and the IP and port were blank. I filled in the IP and port, but it still does not connect. There is no place to supply the password. Nothing has changed in the phone or PC unless it was some behind the scene update.

Ideas?

[chaley]

The usual reason (90% or so) for this to happen is the antivirus on the calibre machine deciding that CC is evil. Antivirus apps update themselves sometimes multiple times per day. The fix is to tell (possibly yet again) the AV to allow connections to calibre.

The second much more rare reason is that the home router restarted and "forgot" information about the devices. Rebooting both the device and the calibre computer usually fixes this.

If you remain stuck after looking that above two, send me a CC debug log. That will tell me what CC is seeing. Sending (or posting) a calibre debug log could be helpful as well, as that would tell us if calibre is seeing anything at all from CC.

[tamhas]

SO, it took me a while to get back to this. The desktop has been rebooted and I have listed calibre.exe in the exception list of Trend Micro. Same results and symptoms. The desktop has a fixed IP address. The IP for the phone is appropriate.

I have attached the CC log. I haven't succeeded in finding one for Calibre itself.

[chaley]

You must ask calibre to produce a debug log. Instructions are here: How do I get help? in the section "Calibre debug log".

I looked at the CC debug log. The last time you tried to connect without using a fixed IP address was on 8 January. At that time CC found calibre's address using mDNS (bonjour), one of the two methods that CC uses to automatically find calibre. This means that the computer running calibre and the device are on the same network and that the device can see that computer. However, the other method, a network broadcast, did not find calibre. That and the fact that CC failed to connect to calibre using the IP address that mDNS provided (the same one you manually added) implies to near the point of certainty that *something* on the calibre computer is blocking calibre from receiving incoming network connections. I can't tell you what.

You can test this by starting your computer in Safe Mode with Networking (how depends on the version of windows) and then testing CC connections. Safe mode is supposed to start without running any AV or other programs.

FWIW: both broadcast and mDNS worked on 18 December.

If Trend Micro is your AV (your post implies that it is) then the problem probably lies in its "Firewall Booster". See https://esupport.trendmicro.com/en-u...t/1107553.aspx

[tamhas]

I contacted Trend Micro and we temporarily turned off all components of Trend Micro and tried again getting the same symptoms. That seems to suggest Trend Micro is not the problem. So, I will try for a Calibre log.

[tamhas]

Here's the Calibre log. This time I got a popup from Windows Firewall asking if I want to allow it. I did, but no change in the result.

[chaley]

Originally Posted by tamhas

Here's the Calibre log. This time I got a popup from Windows Firewall asking if I want to allow it. I did, but no change in the result.

Did you attempt to connect while calibre was in "debug log" mode? If you did then calibre did not receive the packets.

I say again that the CC debug log showed that CC could "see" the calibre computer. The two debug logs say that CC cannot see the calibre program. Something on the desktop is stopping it. I can't say what. FWIW: I have zero confidence in "turning off" AV programs. Countless times we have seen disabled AV programs still running. The best method we know of is to boot in safe mode.

One thing to check: is the network marked as "Private"? If not then CC will not be allowed to connect.


Another thing to check: is the firewall set to allow calibre access?


A third thing to check is to verify that I am not smoking something when I say that the device can "see" the calibre computer. Start the content server in calibre, then on the device start a browser and enter

http://ip address:CS port/

You should see something like the following.

Of course the AV/firewall could block this as well. Another connectivity check is to install a network utility that contains a "PING" function and then see if the device can ping the calibre computer. I have used Ping and DNS to do this, but there are a zillion other choices. You can also do the connectivity check from the calibre computer by opening a CMD window and typing

ping ip-address-of-device

It is getting very close to the point where the only thing I can do is offer you a refund. I simply cannot debug the networking on your desktop computer.

[tamhas]

Yes, I tried connecting.
I *was* on-line with Trend Micro when I did the disable.
Safe mode is not easy since I have a lot of stuff active.
Yes, the network is private (and hasn't changed in months)
Yes on the firewall
With the content server test, and 192.168.100.4:9090 using the values I use from the wireless connection, I get
Got the error: Server Error
while trying to obtain http:192.168.100.4:9090
Connection refused.
Using Ping&DNS the ping fails on the IP address.
On another computer on the network, ping succeeds.
Ping from the desktop to the phone fails.

Is this telling us that I am not getting out of the phone ... it browses and all that just fine, but maybe something has changed for other connections?

[chaley]

Originally Posted by tamhas

With the content server test, and 192.168.100.4:9090 using the values I use from the wireless connection, I get
Got the error: Server Error
while trying to obtain http:192.168.100.4:9090
Connection refused.

The content server cannot use the same port as the wireless connection. See calibre Preferences / Sharing over the net for the current port and status of the content server.


That said, "connection refused" usually says that some computer actively said "no" to the connection request. That leads us back to something on the calibre computer. For example, if on my device I attempt to connect to port 9090 (the WD port) I get this:


If a computer isn't there then usually one gets something like "connection reset" or "timeout".

Using Ping&DNS the ping fails on the IP address.
On another computer on the network, ping succeeds.
Ping from the desktop to the phone fails.

Is this telling us that I am not getting out of the phone ... it browses and all that just fine, but maybe something has changed for other connections?

What you say is not consistent with CC getting an mDNS response from the computer running calibre. However, being not consistent is not the same as impossible.

The device not being able to ping the calibre computer while some other computer can implies that something in the home router is blocking normal intra-network packets. Are the computers that can see each other both cabled? Both using the same WiFi band?

The normal reason for something like this is that the home router is enforcing Wireless Isolation or Guest Mode. I have no idea how this would be turned on without some interaction on your part on the device or on the router. Another possibility is that the device is connected on one wireless band and the calibre computer on another band or on a cable, and the router has stopped transferring between the two. Again, it is difficult to see how this can happen if you changed nothing.

If you haven't changed any router settings then you might consider rebooting the router under the assumption that it changed itself. If you do this then you should power down all the devices connected to the router, reboot the router, then power up the devices.

The problem is that I really have no idea what is going on. We have seen situations where a device simply cannot ever connect to calibre. However, you were able to connect, so something else is going on. IIRC you have more than one device running CC. Do all the devices suffer from this problem?

[chaley]

Some other diagnostics occurred to me overnight.

1) Can the failing device ping itself? If not then something is very strange with the device and/or with the router.

2) Can the failing device ping any other device on your network, including the router? If it can't ping anything or if it can ping only the router then probably the router is enforcing isolation.

3) The inverse is also worth checking. Can any other device ping the failing device? You might see a pattern based on how the two devices are connected to the network. For example, two on the same wifi band can see each other but one on cable and one on wifi cannot.

[tamhas]

OK, starting the Content Server and doing the http://192.168.100.4:8080 works.
So, I retried the wireless connection and it didn't work.
So, I tried the browser on 9090 to see if I got the same you did ... and I got a login screen for OpenEdge Management Console (OpenEdge is a software package I develop in, although I don't use the Management Console).
So, I tried starting the wireless connection on 8090 instead and with CC changed correspondingly, it now connects.
While a conflict over port use makes perfect sense and I know that OpenEdge does some default stuff during install that I pay no attention to, since it relates to functionality I never use, it has been nearly a year since the last OpenEdge install so if this was going to be a conflict, it should have been a conflict all along. There have been no changes to OpenEdge in eons and the only changes to Calibre have been the periodic updates.
We have more than one device running CC, but the other is my wife's and she works off her own copy of Calibre on her own machine. It has happened that I have connected to her copy, but 99% of the time there is no possibility since only one of us will have the wireless connection live at a time.
So, looks like the problem is solved ... and the reason clear ... but why it is a new problem is a mystery.

[tamhas]

Oh, and thanks again for terrific support!

[chaley]

Originally Posted by tamhas

OK, starting the Content Server and doing the http://192.168.100.4:8080 works.
So, I retried the wireless connection and it didn't work.
So, I tried the browser on 9090 to see if I got the same you did ... and I got a login screen for OpenEdge Management Console (OpenEdge is a software package I develop in, although I don't use the Management Console).
So, I tried starting the wireless connection on 8090 instead and with CC changed correspondingly, it now connects.
...

Well, this is a bit embarrassing. The clue was in front of me all along but I simply didn't see it. The calibre log contains the following lines:

Started up in 35.47 seconds with 1173 books
SMART_DEV (   0.04:  0.042) _attach_to_port try ip address "" on port 9090
SMART_DEV (   0.18:  0.000) _attach_to_port socket error on port 9090
SMART_DEV (   0.25:  0.029) _attach_to_port try ip address "" on port 19285
SMART_DEV (   1.11:  0.811) startup_on_demand listening on port 19285

Note the third line, which says that something else is listening on port 9090.

I also see in the CC debug log:

2016-06-27 13:28:18.203:  WDConnection: MDNS ServiceAdded. name=calibre smart device client (on ***** port 25244), address=192.168.100.4, port=25244
2016-06-27 13:28:20.567:  WDConnection: received broadcast response calibre wireless device client (on *****);8080,25244, address 192.168.100.4

Note that the port is not 9090. The reason: when the default port is not available calibre chooses some other port.

Of course, this still leaves us with the question of why it worked in December and stopped working in January.

I suspect that the default setup (no IP address in CC) will work again now that you have it working with a fixed address.

Originally Posted by tamhas

Oh, and thanks again for terrific support!

You are welcome.

[tamhas]

Well, more puzzlement. When my wife tried connecting (different device and computer) she had a similar problem, but following the procedures we used here, we were able to get her connected pretty quickly. Now, I have processed some new books on my copy and tried to connect my phone to Calibre on my computer and it is now failing again.

I am attaching a Calibre debug log ... but I can't seem to find a CC debug log.

[chaley]

Originally Posted by tamhas

Well, more puzzlement. When my wife tried connecting (different device and computer) she had a similar problem, but following the procedures we used here, we were able to get her connected pretty quickly. Now, I have processed some new books on my copy and tried to connect my phone to Calibre on my computer and it is now failing again.

I am attaching a Calibre debug log ... but I can't seem to find a CC debug log.

There isn't a debug log attached to your post.

This FAQ How do I get help? tells you how to send me a CC debug log.