Line decoders
The Select Decoder window shows a context-sensitive list of decoders which can be applied to the current packet. If the packet contains TCP or UDP, this list will include generic line decoders such as Display Number Of Bytes. The following table lists the available line decoders and their behavior.
|
Decoder
|
Shows
|
|---|---|
|
Default Decoder
|
When you select this decoder, the program returns to its default behavior when decoding packets of the current type. Use this selection to stop using any decoder previously selected in the Select Decoder window and restore the program's ability to choose its own decoder.
|
|
Display Number Of Bytes
|
This line decoder displays only the number of bytes in the UDP or TCP payload of the packet.
|
|
Display Text And Binary
|
This line decoder displays 0x00 through 0x1F as their code equivalents (0x00, for example, is <NULL>), displays (non-extended) ASCII characters as ASCII text, and displays any other values as a dot (.).
In contrast, the ASCII part of the Hex view displays the extended ASCII character set (which includes accented characters, for example) and displays all non-ASCII values as dots.
|
|
Display All Lines
|
This line decoder displays only (non-extended) ASCII characters, plus line feed / carriage return (0x0D and 0x0A). When it encounters the first value outside this set, the decoder stops and displays the number of bytes remaining in the payload portion of the UDP or TCP packet.
|
|
Display Fields And Lines
|
This line decoder searches for lines containing semi-colons (;). Each line with a semi-colon is split in two, with the part before the semi-colon treated as the label and the part to the right of the semi-colon treated as the data. Lines containing text without semi-colons are treated as for the Display All Lines decoder above. That is, non-extended ASCII text is displayed until the first non-ASCII character is reached. The decoder then displays the number of bytes remaining in the payload of the TCP or UDP packet.
This decoder is particularly useful for scanning through the Label;Value pairs found in HTTP and FTP packets, particularly when the transactions are taking place on ports other than the default port 80 (HTTP) or port 21 (FTP).
|
|
Display Text Lines Only
|
This line decoder displays all the non-extended ASCII characters, plus line feeds and carriage returns (LF/CR), ignoring all other characters. If no LF/CR is encountered, lines are automatically wrapped at 120 characters.
|
|
Display Dotted Names Only
|
This line decoder searches for lines of non-extended ASCII text containing the period character(.). It displays each such line. All other lines are ignored. This decoder is useful when scanning for file names and IP names and addresses that use dotted notation.
|