What Tcp Ip Do When There Is Packet Loss?

what tcp ip do when there is packet loss?

iPositive Security: [DIY] Tools - Using Hping

I would like to mention one switch in the IP options category: --rand-source. This hping switch selects the source address of all packets randomly. This can therefore, be used to do (stress) testing stateful firewalls. But it can also potentially fill up the state table, in turn causing legit users & traffic to drop off. So, need to keep this when using this option.

Okay, moving on.

By default, hping sends TCP packets with no tcp flags set, and target host's port 0, continuously. A target system will respond with a RST packet, confirming that it is live.

roobr/>  -9 --listen listen mode
...
snip
...

RAW IP mode sends the packets without a TCP or UDP headers. To send raw IP packets to target, use the -0 or --rawip switch:

roo/span>

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Final mode is the Listen mode, activated by -9 or --listen switch. Basically, when started in listen mode, hping waits] for an incoming packet. hping expects a signature in the incoming packet. Once it finds the signature, hping then dumps the packet, starting -from- the signature -to- the packet end.

For example, on my *nix box, I start hping in listen mode and set the signature as 'JackP0t'. Note that in listen mode, we need to specify the interface to listen on [in case there are multiple interfaces on your box]. Next on the Windows target box, I start hping and give it the file 'confidential_file' as the data input. Remember this data file content will be 'prepended' with the signature 'JackP0t' when it goes out in the packet.

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Chris Sanders

roodata.Secret data.Secret data.Secret data.Secret data.Secret data.Secret data.Secret data.Secret data.Secret data.Secret data.Secret data.Secret data.Secret data.Secret data.Secret data. <--- content in the file 'confidential_file' which we sent in the packets. hping listener sees the signature 'JackP0t' and then dumps bytes that follow.

From Windows system:

C:\Documents and Settings\Administrator\Desktop\hping2.win32>hping --data 100 --file confidential_file.txt -e JackP0t 172.72.5.1 -V --end <--- we have set a data size of 100 bytes, specified the file 'confidential_file.txt' as data input, set 'JackP0t' as the signature, used a Verbose option to see responses and lastly, used the --end option to tell us when the file reaches EOF.

using AMD PCNET Family PCI Ethernet Adapter - Packet Scheduler Miniport, addr: 172.72.5.139, MTU: 1500
HPING (XPSP2) 172.72.5.1 (AMD PCNET Family PCI Ethernet Adapter - Packet Scheduler Miniport 172.72.5.1): NO FLAGS are set, 40 headers + 100 data bytes
[main] memlockall(): No error
Warning: can't disable memory paging!
EOF reached, wait some second than press ctrl+c
len=46 ip=172.72.5.1 ttl=64 DF id=0 tos=0 iplen=40
sport=0 flags=RA seq=0 win=0 rtt=16.0 ms
seq=0 ack=141 sum=7441 urp=0
EOF reached, wait some second than press ctrl+c
len=46 ip=172.72.5.
1 ttl=64 DF id=0 tos=0 iplen=40
sport=0 flags=RA seq=1 win=0 rtt=0.0 ms
seq=0 ack=26600 sum=17da urp=0

Do note that hping does NOT allow us to scan or send packets to a range of IP addresses. However, we can automate it using a bit of shell scripting.

Let's say we want to send 1 single SYN packet to all 'known' alias ports on all hosts in 172.72.5.0/24 network. This can be done as follows:

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