Switch send strange replies to ICMP requests:

 

84 bytes from 192.168.2.130: icmp_seq=682 ttl=64 time=1.997 ms

wrong total length 104 instead of 84

84 bytes from 192.168.2.130: icmp_seq=683 ttl=64 time=2.194 ms

wrong total length 104 instead of 84

84 bytes from 192.168.2.130: icmp_seq=684 ttl=64 time=2.044 ms

wrong total length 104 instead of 84

 

It adds exactly 20 bytes to any ping request.

I decided to see what is this 20 bytes with tcpdump:

 

20:11:16.979893 IP gw.service.local > comm.3.local: ICMP echo request, id 49700, seq 3, length 64

        0x0000:  4500 0054 4a6a 0000 4001 aa6b c0a8 0201

        0x0010:  c0a8 0282 0800 4c8b c224 0003 000b db50

        0x0020:  2aed f800 0809 0a0b 0c0d 0e0f 1011 1213

        0x0030:  1415 1617 1819 1a1b 1c1d 1e1f 2021 2223

        0x0040:  2425 2627 2829 2a2b 2c2d 2e2f 3031 3233

        0x0050:  3435 3637

20:11:16.981723 IP comm.3.local > gw.service.local: ICMP echo reply, id 49700, seq 3, length 84

        0x0000:  4500 0068 0e5a 0000 4001 e667 c0a8 0282

        0x0010:  c0a8 0201 0000 4c5e c224 0003 000b db50

        0x0020:  2aed f800 0809 0a0b 0c0d 0e0f 1011 1213

        0x0030:  1415 1617 1819 1a1b 1c1d 1e1f 2021 2223

        0x0040:  2425 2627 2829 2a2b 2c2d 2e2f 3031 3233

        0x0050:  3435 3637 0765 2f73 7061 6e3e 3c2f 7464

        0x0060:  3e20 3c74 6420 636c

 

 

this 20 bytes are: 0765 2f73 7061 6e3e 3c2f 7464 3e20 3c74 6420 636c or in ascii = "/span></td> <td cl".

Some part of html :)

What is it? firmware bug?