Find the answer to your Linux question:
Results 1 to 2 of 2
Hi all! I've a question. if i digit this: Code: hping -m 32 --data 140 -c 1 localhost (with an mtu = 32byte) i have, this output Code: HPING localhost ...
Enjoy an ad free experience by logging in. Not a member yet? Register.
  1. #1
    Just Joined!
    Join Date
    Apr 2010
    Posts
    9

    hping, fragmented packet


    Hi all! I've a question.

    if i digit this:
    Code:
    hping -m 32 --data 140 -c 1 localhost
    (with an mtu = 32byte) i have, this output
    Code:
    HPING localhost (lo 127.0.0.1): NO FLAGS are set, 40 headers + 140 data bytes
    len=40 ip=127.0.0.1 ttl=64 DF id=0 sport=0 flags=RA seq=0 win=0 rtt=0.3 ms
    
    --- localhost hping statistic ---
    1 packets tramitted, 1 packets received, 0% packet loss
    round-trip min/avg/max = 0.3/0.3/0.3 ms
    I RECEIVED the response packet!

    but if i digit:
    Code:
    hping -m 30 --data 140 -c 1 localhost
    (an mtu = 30)

    the output is:
    Code:
    HPING localhost (lo 127.0.0.1): NO FLAGS are set, 40 headers + 140 data bytes
    
    --- localhost hping statistic ---
    1 packets tramitted, 0 packets received, 100% packet loss
    round-trip min/avg/max = 0.0/0.0/0.0 ms
    i.e: I don't receive packet....WHY? WHY? WHY?

  2. #2
    Linux Engineer Kloschüssel's Avatar
    Join Date
    Oct 2005
    Location
    Italy
    Posts
    773
    Do you know what MTU is and how routers behave if it is set to values so small that the packet header can't be sent in one transmission unit but becomes sliced and the router drops the packet cause it is no longer valid for him?

    Normal MTU values nowadays are somewhere around 1500 to 9000 depending on your network hardware (ethernet, gigabit ethernet, ..) but surely not 30 bytes. You would produce more header traffic than packet payload.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •