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Many ISPs have taken to naming their dial-up PPP or SLIP addresses with the word 'dial', 'ppp', 'modem' or 'slip'. If you see these, there is a good chance that the source of the scan is a modem user. ... (or port) is active. If it isn't, then the server responds with a RESET packet. Both the SYN-ACK and the RESET packets can be used to ... ................
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