Hello, While in telnet session to a remote ADSL Cisco router, the session freezes and then disconnects. I see that the client side sends a [RST, ACK] after a lot of retransmissions. What is the cause of this behavior? The connection on each side is not saturated.
You can find the pcap file here: https://send.firefox.com/download/0cc...
Thank you very much.
All packets up till frame 2076 are sent to the gateway with mac-address d4:21:22:71:fb:20 (OUI: Sercomm), then starting with frame 2077, packets are sent to a different Sercomm mac address (94:4a:0c:4a:4b:10).
The funny part is that the TCP/RST in frame 2086 is sent to the original mac-address again. The ACK in frame 2087 has ack value 761 (acking frame 2073), proving the data that was sent in frame 2077-2085 never reached the server.
I would look at (at least) the ARP / VRRP / HSRP packets while you do your capture. But preferably all packets to see what is happening on your subnet during this problem.
You are absolutely right. There was another router with the same ip add on the network. Thank you very much.
Comments
Looks like after 30 seconds of no response from the router the client gives up and closes the session.
Can you make a capture closer to the router to see if it is not responding or if it is, are the packets not making it to the client.