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TCP Retransmission (Port numbers reused) followed by Destination Unreachable


I am having issues with my internet for some time now (1-2 months) and unfortunately, my provider cannot find the cause for it. The issue appears periodically (not every day) and so far only in the evening at a random time. Both wired and wireless connections get affected and the connected devices show 'No internet' status for the network. I have tried ping with -n 200-500 and there are usually 3-15 packages lost. Ping is usually fine, although sometimes it gets up to 200-300 ms. According to my provider all is fine with their network. The connection is over optical wire. I'd also like to point out that my IP TV (from the same provider) has no issues at all during these periods.

I have recenlty found wireshark and made captures when the issue is present - both on wireless and ethernet. I do not understand the results though and would be grateful if someone can help with understanding them. What caught my attention are two record types that have not appeared while the connection is good:

23679 1198.088658 TCP 66 [TCP Retransmission] [TCP Port numbers reused] 2437 → 443 [SYN] Seq=0 Win=64240 Len=0 MSS=1460 WS=256 SACK_PERM=1

23680 1198.090012 ICMP 70 Destination unreachable (Communication administratively filtered)

These always go one after the other. Here are links to the whole files: 1. Ethernet Capture 2. Wireless capture

I apologize if the information is not enough, this is the first time I am having such issue. I'd be happy to provide any additional information that might be useful.