[Freedombox-discuss] Element (matrix-synapse client) problems. More info, pointing to server.

A. F. Cano afc54 at comcast.net
Tue Oct 27 03:14:18 GMT 2020 

On Tue, Sep 29, 2020 at 08:16:30AM -0400, A. F. Cano wrote:
> On Mon, Sep 28, 2020 at 10:23:53PM +0200, permondes - sagen wrote:
> >    Isn't there also an update to matrix-synapse waiting to be installed with
> >    20.14.1? Maybe that already helps?
> >    Dietmar

Well, I'm now running 20.16 and it says it's up to date.

> Surprisingly, when I woke up this morning, the element icon didn't have
> the red X any more and the not accessible error message was gone.  I
> could add the room and invite a user to an existing room, so things are
> back to normal.  Not sure what happened.  Some libs got upgraded on the
> FreedomBox overnight but they don't appear to be obviously related to
> matrix-synapse.
> 
> I have encountered this situation (the red X appearing randomly and then
> disappearing a few days later) but it didn't affect video conferencing
> between established users in existing rooms.  This time I found out that
> it does affect room creation and invitations, at least.
> 
> So, problem solved for now...  Thanks for the suggestions.  I have
> installed wireshark and will learn how to use it in case it happens
> again.

Unfortunately, at the next reboot the problem reappeared and has not
gone away, even after a second reboot due to more upgrades.

So I ran a test.  Element is on a local machine (192.168.200.109) and
the FreedomBox is (internal interface) at 192.168.200.27.  There is an
internal router (no firewall) between the 2.

Started wireshark and filtered for packets to the FreedomBox.  Started
capturing and then started Element.  Packets 1-87 gave no errors.  The
first packets in red were the RST ones.  Below are packets 88-106.
After that the sets of red-highlighed packets repeated regularly until I
stopped the capture.

I had to manually edit the captured output since it was impossible to
copy/paste from the wireshark screen and a lot of info is redundant and
it was hard to read.  Hopefully there is enough information to point to 
the cause.  I'm not sure why there are RST packets.  All the
explanations I've found imply that firewalls with closed ports are the
likely cause, but unless the FreedomBox firewall is causing this, I'm at
a loss since there are no other firewalls between the client and the
matrix server on the FreedomBox.

Additional info: Pegatron_* is the machine where the Element client is.
PcEngine_* is where the FreedomBox/matrix server is.
Blank lines between the packets and I've tried to align the columns of
the first line of each packet.

The first RST is in packet 91.  Can anyone see what is causing the RST
packets? I'm not familiar with what should be happening between the
client and the matrix server at startup in such detail but, as
previously discussed, the symptom of this is not being able to invite
users to rooms.  Is there something significant about port 60428? or is
it randomly assigned?  Is this some kind of control port?  On the
other hand, port 60428 is first used without error in packet 48 and for
quite a few other packets after that.  Any clues, anyone?

Thanks

Augustine

So, on startup of the client this is what happens:


No.	Time	Source		Destination	Protocol Length	Info

88  2.639621077 192.168.200.109 192.168.200.27  TCP	 66	60428 → 8118 [FIN, ACK] Seq=261 Ack=264
Win=64256 Len=0 TSval=1718743751 TSecr=2239421113
Frame 88: 66 bytes on wire (528 bits), 66 bytes captured (528 bits) on interface 0
Ethernet II, Src: Pegatron_20:9e:4e (60:02:92:20:9e:4e), Dst: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa)
Internet Protocol Version 4, Src: 192.168.200.109, Dst: 192.168.200.27
Transmission Control Protocol, Src Port: 60428, Dst Port: 8118, Seq: 261, Ack: 264, Len: 0

89  2.639720909 192.168.200.109 192.168.200.27	TCP	 74	 60442 → 8118 [SYN] Seq=0 Win=64240 Len=0
MSS=1460 SACK_PERM=1 TSval=1718743751 TSecr=0 WS=256
Frame 89: 74 bytes on wire (592 bits), 74 bytes captured (592 bits) on interface 0
Ethernet II, Src: Pegatron_20:9e:4e (60:02:92:20:9e:4e), Dst: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa)
Internet Protocol Version 4, Src: 192.168.200.109, Dst: 192.168.200.27
Transmission Control Protocol, Src Port: 60442, Dst Port: 8118, Seq: 0, Len: 0

90  2.639774748 192.168.200.27 192.168.200.109	TCP	1514	8118 → 60428 [ACK] Seq=264 Ack=261 Win=65024
Len=1448 TSval=2239421113 TSecr=1718742204 [TCP segment of a reassembled PDU]
Frame 90: 1514 bytes on wire (12112 bits), 1514 bytes captured (12112 bits) on interface 0
Ethernet II, Src: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa), Dst: Pegatron_20:9e:4e (60:02:92:20:9e:4e)
Internet Protocol Version 4, Src: 192.168.200.27, Dst: 192.168.200.109
Transmission Control Protocol, Src Port: 8118, Dst Port: 60428, Seq: 264, Ack: 261, Len: 1448

91  2.639792153 192.168.200.109 192.168.200.27	TCP	54	60428 → 8118 [RST] Seq=261 Win=0 Len=0
Frame 91: 54 bytes on wire (432 bits), 54 bytes captured (432 bits) on interface 0
Ethernet II, Src: Pegatron_20:9e:4e (60:02:92:20:9e:4e), Dst: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa)
Internet Protocol Version 4, Src: 192.168.200.109, Dst: 192.168.200.27
Transmission Control Protocol, Src Port: 60428, Dst Port: 8118, Seq: 261, Len: 0

92  2.639933764 192.168.200.27 192.168.200.109	TCP	1514	8118 → 60428 [ACK] Seq=1712 Ack=261
Win=65024 Len=1448 TSval=2239421113 TSecr=1718742204 [TCP segment of a reassembled PDU]
Frame 92: 1514 bytes on wire (12112 bits), 1514 bytes captured (12112 bits) on interface 0
Ethernet II, Src: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa), Dst: Pegatron_20:9e:4e (60:02:92:20:9e:4e)
Internet Protocol Version 4, Src: 192.168.200.27, Dst: 192.168.200.109
Transmission Control Protocol, Src Port: 8118, Dst Port: 60428, Seq: 1712, Ack: 261, Len: 1448

93  2.639942839 192.168.200.109 192.168.200.27	TCP	54	60428 → 8118 [RST] Seq=261 Win=0 Len=0
Frame 93: 54 bytes on wire (432 bits), 54 bytes captured (432 bits) on interface 0
Ethernet II, Src: Pegatron_20:9e:4e (60:02:92:20:9e:4e), Dst: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa)
Internet Protocol Version 4, Src: 192.168.200.109, Dst: 192.168.200.27
Transmission Control Protocol, Src Port: 60428, Dst Port: 8118, Seq: 261, Len: 0

94  2.640060272 192.168.200.27 192.168.200.109	TCP	1514	8118 → 60428 [ACK] Seq=3160 Ack=261
Win=65024 Len=1448 TSval=2239421113 TSecr=1718742204 [TCP segment of a reassembled PDU]
Frame 94: 1514 bytes on wire (12112 bits), 1514 bytes captured (12112 bits) on interface 0
Ethernet II, Src: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa), Dst: Pegatron_20:9e:4e (60:02:92:20:9e:4e)
Internet Protocol Version 4, Src: 192.168.200.27, Dst: 192.168.200.109
Transmission Control Protocol, Src Port: 8118, Dst Port: 60428, Seq: 3160, Ack: 261, Len: 1448

95  2.640067346 192.168.200.109 192.168.200.27	TCP	54	60428 → 8118 [RST] Seq=261 Win=0 Len=0
Frame 95: 54 bytes on wire (432 bits), 54 bytes captured (432 bits) on interface 0
Ethernet II, Src: Pegatron_20:9e:4e (60:02:92:20:9e:4e), Dst: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa)
Internet Protocol Version 4, Src: 192.168.200.109, Dst: 192.168.200.27
Transmission Control Protocol, Src Port: 60428, Dst Port: 8118, Seq: 261, Len: 0

96  2.640181090 192.168.200.27 192.168.200.109	TCP	1514	8118 → 60428 [ACK] Seq=4608 Ack=261
Win=65024 Len=1448 TSval=2239421113 TSecr=1718742204 [TCP segment of a reassembled PDU]
Frame 96: 1514 bytes on wire (12112 bits), 1514 bytes captured (12112 bits) on interface 0
Ethernet II, Src: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa), Dst: Pegatron_20:9e:4e (60:02:92:20:9e:4e)
Internet Protocol Version 4, Src: 192.168.200.27, Dst: 192.168.200.109
Transmission Control Protocol, Src Port: 8118, Dst Port: 60428, Seq: 4608, Ack: 261, Len: 1448

97  2.640186855 192.168.200.109 192.168.200.27	TCP	54	60428 → 8118 [RST] Seq=261 Win=0 Len=0
Frame 97: 54 bytes on wire (432 bits), 54 bytes captured (432 bits) on interface 0
Ethernet II, Src: Pegatron_20:9e:4e (60:02:92:20:9e:4e), Dst: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa)
Internet Protocol Version 4, Src: 192.168.200.109, Dst: 192.168.200.27
Transmission Control Protocol, Src Port: 60428, Dst Port: 8118, Seq: 261, Len: 0

98  2.640212703 192.168.200.27 192.168.200.109	HTTP	909	HTTP/1.1 503 Connect failed (text/html)
Frame 98: 909 bytes on wire (7272 bits), 909 bytes captured (7272 bits) on interface 0
Ethernet II, Src: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa), Dst: Pegatron_20:9e:4e (60:02:92:20:9e:4e)
Internet Protocol Version 4, Src: 192.168.200.27, Dst: 192.168.200.109
Transmission Control Protocol, Src Port: 8118, Dst Port: 60428, Seq: 6056, Ack: 261, Len: 843
[6 Reassembled TCP Segments (6898 bytes): #86(263), #90(1448), #92(1448), #94(1448), #96(1448), #98(843)]
Hypertext Transfer Protocol
Line-based text data: text/html (196 lines)

99  2.640214653 192.168.200.109 192.168.200.27	TCP	54	60428 → 8118 [RST] Seq=261 Win=0 Len=0
Frame 99: 54 bytes on wire (432 bits), 54 bytes captured (432 bits) on interface 0
Ethernet II, Src: Pegatron_20:9e:4e (60:02:92:20:9e:4e), Dst: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa)
Internet Protocol Version 4, Src: 192.168.200.109, Dst: 192.168.200.27
Transmission Control Protocol, Src Port: 60428, Dst Port: 8118, Seq: 261, Len: 0

100 2.640216606 192.168.200.27 192.168.200.109	TCP	66	8118 → 60428 [FIN, ACK] Seq=6899 Ack=261
Win=65024 Len=0 TSval=2239421113 TSecr=1718742204
Frame 100: 66 bytes on wire (528 bits), 66 bytes captured (528 bits) on interface 0
Ethernet II, Src: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa), Dst: Pegatron_20:9e:4e (60:02:92:20:9e:4e)
Internet Protocol Version 4, Src: 192.168.200.27, Dst: 192.168.200.109
Transmission Control Protocol, Src Port: 8118, Dst Port: 60428, Seq: 6899, Ack: 261, Len: 0

101 2.640218935 192.168.200.109 192.168.200.27	TCP	54	60428 → 8118 [RST] Seq=261 Win=0 Len=0
Frame 101: 54 bytes on wire (432 bits), 54 bytes captured (432 bits) on interface 0
Ethernet II, Src: Pegatron_20:9e:4e (60:02:92:20:9e:4e), Dst: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa)
Internet Protocol Version 4, Src: 192.168.200.109, Dst: 192.168.200.27
Transmission Control Protocol, Src Port: 60428, Dst Port: 8118, Seq: 261, Len: 0

102 2.640220358 192.168.200.27 192.168.200.109	TCP	66	8118 → 60428 [ACK] Seq=6900 Ack=262
Win=65024 Len=0 TSval=2239421113 TSecr=1718743751
Frame 102: 66 bytes on wire (528 bits), 66 bytes captured (528 bits) on interface 0
Ethernet II, Src: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa), Dst: Pegatron_20:9e:4e (60:02:92:20:9e:4e)
Internet Protocol Version 4, Src: 192.168.200.27, Dst: 192.168.200.109
Transmission Control Protocol, Src Port: 8118, Dst Port: 60428, Seq: 6900, Ack: 262, Len: 0

103 2.640222411 192.168.200.109 192.168.200.27	TCP	54	60428 → 8118 [RST] Seq=262 Win=0 Len=0
Frame 103: 54 bytes on wire (432 bits), 54 bytes captured (432 bits) on interface 0
Ethernet II, Src: Pegatron_20:9e:4e (60:02:92:20:9e:4e), Dst: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa)
Internet Protocol Version 4, Src: 192.168.200.109, Dst: 192.168.200.27
Transmission Control Protocol, Src Port: 60428, Dst Port: 8118, Seq: 262, Len: 0

104 2.640231299 192.168.200.27 192.168.200.109	TCP	74	8118 → 60442 [SYN, ACK] Seq=0 Ack=1
Win=65160 Len=0 MSS=1460 SACK_PERM=1 TSval=2239421113 TSecr=1718743751 WS=128
Frame 104: 74 bytes on wire (592 bits), 74 bytes captured (592 bits) on interface 0
Ethernet II, Src: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa), Dst: Pegatron_20:9e:4e (60:02:92:20:9e:4e)
Internet Protocol Version 4, Src: 192.168.200.27, Dst: 192.168.200.109
Transmission Control Protocol, Src Port: 8118, Dst Port: 60442, Seq: 0, Ack: 1, Len: 0

105 2.640249179 192.168.200.109 192.168.200.27	TCP	66	60442 → 8118 [ACK] Seq=1 Ack=1 Win=64256
Len=0 TSval=1718743752 TSecr=2239421113
Frame 105: 66 bytes on wire (528 bits), 66 bytes captured (528 bits) on interface 0
Ethernet II, Src: Pegatron_20:9e:4e (60:02:92:20:9e:4e), Dst: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa)
Internet Protocol Version 4, Src: 192.168.200.109, Dst: 192.168.200.27
Transmission Control Protocol, Src Port: 60442, Dst Port: 8118, Seq: 1, Ack: 1, Len: 0

106 2.640294837 192.168.200.109 192.168.200.27	HTTP	326	CONNECT <sub-domain>.freedombox.rocks:443 HTTP/1.1
Frame 106: 326 bytes on wire (2608 bits), 326 bytes captured (2608 bits) on interface 0
Ethernet II, Src: Pegatron_20:9e:4e (60:02:92:20:9e:4e), Dst: PcEngine_3f:92:aa (00:0d:b9:3f:92:aa)
Internet Protocol Version 4, Src: 192.168.200.109, Dst: 192.168.200.27
Transmission Control Protocol, Src Port: 60442, Dst Port: 8118, Seq: 1, Ack: 1, Len: 260
Hypertext Transfer Protocol

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