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connectivity stop between client and server

asked 2018-08-30 15:01:08 +0000

Sabah gravatar image

Hi all,

My question is that I getting a lot of Retransmission packets with the connection between the client and Server. basically, I have a Client ( phone application installed on my cell phone) with IP address, and Server with IP address Sometimes the connectivity stop between them. Does anyone have any idea why? Unfortunately, I don't have enough points to upload my Wireshark file, anybody have any idea how can I share my file.


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You can share it via other online services such as Cloudshark, Google Drive, etc.

cmaynard gravatar imagecmaynard ( 2018-08-30 15:59:28 +0000 )edit

Thanks you

Sabah gravatar imageSabah ( 2018-08-30 23:19:59 +0000 )edit

Please check the link below for the packets

link text

Sabah gravatar imageSabah ( 2018-08-30 23:21:01 +0000 )edit

Seems that the TSecr value does of the SYN ACK does not match the TSval of the SYN packet. See similiar problem here:

Christian_R gravatar imageChristian_R ( 2018-08-31 16:14:46 +0000 )edit

Hi, I don't think that same issue since the TSval of the first SYN matches the TSect of the SYN/ACK, but the client doesn't reply with ACK after the 3-way shake messages, but instead, it sent the RTO of the first SYN.

Sabah gravatar imageSabah ( 2018-08-31 18:49:39 +0000 )edit

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answered 2018-08-31 00:06:21 +0000

martyvis gravatar image

I presume you are capturing this on the wired network and your phone is on WiFi. It looks to me that your WiFi network has a poor physical layer connection to your phone. You can see phone initiated the session (SYN flag) at frames 3,5,7, and 14. For each one your server ACKnowldges (SYN/ACK). The SYNs are coming in at increasing inter. Between the SYN at frame 8 and 14 there are 3 SYNACKs from your server that don't seem to be heard.

Try moving your WiFi to another channel as your probably are getting a lot of interference.

Basically TCP is doing it's job from what I can see

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Hi I don't think there is an issue with my wifi signal, I can ping between the client and server perfectly. the only thing that confuses me that the client doesn't reply to the server with ACK but reply with RTO of the SYN message, please check eq 2 and all of that happens after 3 to 5 min of turning the screen of my cell phone off.

Sabah gravatar imageSabah ( 2018-08-31 18:45:12 +0000 )edit

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Asked: 2018-08-30 15:01:08 +0000

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Last updated: Aug 31 '18