TCP IP Illustrated

Here is where we reboot the server host and this one

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Unformatted text preview: ry of the connections that existed before it was rebooted, it knows nothing about the connection that the data segment references. The rule of TCP is that the receiver responds with a reset. bsdi % telnet svr4 discard Trying 140.252.13.34... Connected to svr4. start the client file:///D|/Documents%20and%20Settings/bigini/Docu...homenet2run/tcpip/tcp-ip-illustrated/tcp_conn.htm (21 of 37) [12/09/2001 14.47.16] Chapter 18. TCP Connection Establishment and Termination Escape character is '^]' hi there another line Connection closed by foreign host. this line is sent OK. here is where we reboot the server host and this one elicits a reset Figure 18.16 shows the tcpdump output for this example. (We have removed from this output the window advertisements, the type-of-service information, and the MSS announcements, since they add nothing to the discussion.) 1 0.0 2 0.004811 (0.0048) 3 0.006516 (0.0017) 4 5.167679 (5.1612) 5 5.201662 (0.0340) 194.909929 6 (189.7083) 194.914957 7 (0.0050) 194.915678 8 (0.0007) 194.918225 9 (0.0025) bsdi.1102 > svr4.discard: S1591752193:1591752193(0) svr4.discard > bsdi.1102: S26368001:26368001(0) ack 1591752194 bsdi.1102 > svr4.discard: . ack 1 bsdi.1102 > svr4.discard: P 1:11(10) ack 1 svr4.discard > bsdi.1102: . ack 11 bsdi.1102 > svr4.discard: P 11:25(14) ack 1 arp who-has bsdi tell svr4 arp reply bsdi is-at 0:0:c0:6f:2d:40 svr4.discard > bsdi.1102: R26368002:26368002 (0) Figure 18.16 Reset in response to data segment on a half-open connection. Lines 1-3 are the normal connection establishment. Line 4 sends the line "hi there" to the discard server, and line 5 is the acknowledgment. At this point we disconnect the Ethernet cable from svr4, reboot it, and reconnect the cable. This takes almost 190 seconds. We then type the next line of input to the client ("another line") and when we type the return key the line is sent to the server (line 6 in Figure 18.16). This elicits a response from the server, but note that since the server was rebooted, its ARP cache is empty, so a...
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This test prep was uploaded on 04/04/2014 for the course ECE EL5373 taught by Professor Guoyang during the Spring '12 term at NYU Poly.

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