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Packet-o-matic can be quite complicated due to the infinite number of possibilities it provides. Here are a few configuration example that you may find useful to understand how certain aspects can be configured.
Scan for a DOCSIS stream using a DVB card
The following example will scan for a DOCSIS stream. Once the stream is acquired, it will stay tuned on it.
Use input docsis and set it's mode to scan.
pom> input type set docsis pom> input mode set scan
To see what will be going on, enable more verbose debug in the console.
pom> debug cli set 3
Now start the input and wait for a DOCSIS stream to be found.
pom> input start
Once the stream is found, you'll see the message “Downstream acquired !”. At this point, input_docsis switch to mode normal and you can simply save the config to remember the details of the DOCSIS stream.
If the previous scan didn't find anything, the modulation is probably wrong. Try QAM64 instead of QAM256.
pom> input parameter set modulation QAM64
Kill all the MSN connections
The following example will reset all the connections on the TCP port 1863 which is the port used by MSN. This example assume that the MSN connection is going through the interface eth0.
Use input pcap to sniff on eth0. This is the default interface.
pom> input type set pcap pom> input start
Add a rule to match one way of the MSN connections on TCP port 1863.
pom> rule add tcp.dport == 1863 Added rule with id 0 pom> rule enable 0
Add the tcpkill target to our new rule. By default, this target will send TCP RST packets on the interface eth0.
pom> target add 0 tcpkill Added target with id 0 to rule 0 pom> target start 0 0
Dump raw DOCSIS packets into a pcap file
The following example set the input type to docsis, create a rule and a target to save the raw docsis stream in a file name docsis.cap. The specific settings for input docsis regarding frequency and other tuning parameters were omitted.
pom> input type set docsis
Tell the docsis input to return packets at the docsis layer.
pom> input parameter set outlayer docsis
Once configured correctly, start the input.
pom> input start
Add a rule that matches the docsis layer.
pom> rule add docsis Added rule with id 0 pom> rule enable 0
Add a target pcap to save the packets.
pom> target add 0 pcap Added target with id 0 to rule 0
Specify that the file will contain docsis packets.
pom> target parameter set 0 0 layer docsis pom> target parameter set 0 0 filename docsis.cap pom> target start 0 0