Hi gurus,
I'm wondering how to calculate the checksum included in a CDP packet. ( df f0 in the second line )
01 00 0c cc cc cc 00 e0 1e d5 d5 15 01 1e aa aa # ........ ........ 03 00 00 0c 20 00 01 b4 df f0 00 01 00 06 52 31 # .... ... ......R1 00 02 00 11 00 00 00 01 01 01 cc 00 04 c0 a8 0a # ........ ........ 01 00 03 00 0d 45 74 68 65 72 6e 65 74 30 00 04 # .....Eth ernet0.. 00 08 00 00 00 01 00 05 00 d8 43 69 73 63 6f 20 # ........ ..Cisco 49 6e 74 65 72 6e 65 74 77 6f 72 6b 20 4f 70 65 # Internet work Ope 72 61 74 69 6e 67 20 53 79 73 74 65 6d 20 53 6f # rating S ystem So 66 74 77 61 72 65 20 0a 49 4f 53 20 28 74 6d 29 # ftware . IOS (tm) 20 31 36 30 30 20 53 6f 66 74 77 61 72 65 20 28 # 1600 So ftware ( 43 31 36 30 30 2d 4e 59 2d 4c 29 2c 20 56 65 72 # C1600-NY -L), Ver 73 69 6f 6e 20 31 31 2e 32 28 31 32 29 50 2c 20 # sion 11. 2(12)P, 52 45 4c 45 41 53 45 20 53 4f 46 54 57 41 52 45 # RELEASE SOFTWARE 20 28 66 63 31 29 0a 43 6f 70 79 72 69 67 68 74 # (fc1).C opyright 20 28 63 29 20 31 39 38 36 2d 31 39 39 38 20 62 # (c) 198 6-1998 b 79 20 63 69 73 63 6f 20 53 79 73 74 65 6d 73 2c # y cisco Systems, 20 49 6e 63 2e 0a 43 6f 6d 70 69 6c 65 64 20 54 # Inc..Co mpiled T 75 65 20 30 33 2d 4d 61 72 2d 39 38 20 30 36 3a # ue 03-Ma r-98 06: 33 33 20 62 79 20 64 73 63 68 77 61 72 74 00 06 # 33 by ds chwart.. 00 0e 63 69 73 63 6f 20 31 36 30 31 # ..cisco 1601I would like to validate the received packets.