Legacy Manual

Engine Options


Packet Type



Timeout Speed



Time interval between hop traces



Packet Size

The Packet Size can make a considerable difference in latency performance. Normally, you want to use a relatively small number here. The default is 56 bytes, but in some cases you might need to lower this (especially on TCP port 80 packets, which sometimes get dropped unless they are 40 bytes). 1500 is lot of data, and should be used with great care. A 1500 byte packet means PingPlotter will be sending out 30-50 K per second worth of data, which can cause its own problems (and makes measuring latency more challenging).

ToS/DSCP header byte

This is relatively advanced course material – ie: if you don’t know what this means, just leave it at 0.

The DSCP byte is often used by network providers to determine packet priority and sometimes make other decisions about the data. There may be an occasion where you want to manipulate this byte and test network performance. VoIP data, for example, is often characterized by a value in the DSCP byte.

This byte can be edited as Decimal, Hex, or Binary by hitting the button beside the edit field. The display on the button shows the current format this value is displayed in.

Note that under Windows XP and newer operating systems, a registry setting needs to be modified to allow this byte to be used. This is a system-wide setting that allows applications to write their own values into this byte. If your system needs to have this value set, PingPlotter will prompt to see if you want this setting changed (and a reboot will be required) as soon as you modify the value in this field.

Starting Hop

Sometimes hop 1 or  2 might never respond. Rather than continuing to pound away at these hops and never getting a response, it sometimes makes sense to just ignore the first hop or 2. This is totally normal on lots of cable modems, and can happen on any connection – where the first hop is always "silent". Ignoring the first non-responding hops will save some resources.

TCP Specific Settings

When using TCP packets, you can specify which target port to use. Usually, you’ll want to use port 80 here, but you’re welcome to use any reasonable port. Windows firewall blocks creation of TCP packets, so you’ll need to use WinPCap to create packets under that OS (and possibly others).

Use non-threaded Name Lookups

This makes PingPlotter do all DNS lookups in the main application thread. If you’re having DNS lookup problems, it might be worth trying. Some older Windows OS versions (Windows NT) may not like multiple name lookups being done. This also turns on a separate lookup if you're doing single-threaded tracing.

Maximum concurrent requests

PingPlotter sends multiple requests simultaneously, but we need to put a limit on it so we’re not queuing more packets than we can send. Set this to 1 to only have one request out there at once. For ICMP types, this is concurrent *threads*. For UDP and TCP (which share a single thread for all packets), this is requests.

Setting this too high can cause PingPlotter to crash, especially on old operating systems. 45 is proven safe. If you have a really fast trace interval, you may need to increase this number to support the trace interval. Usually, you want to lower the "Timeout Speed" setting before raising this, as that might be adequate.


Note: This is an advanced option that should probably not be changed. This is used to diagnose network problems when specific *data* is sent - which is a highly unlikely problem for most networks.

By default, PingPlotter (basically) pads the outgoing packet with repeating string representing the current PingPlotter version and name. An example of this is PingPlotter250, repeated over and over to fill the cargo. If you suspect that your network may be having problems when you send specific byte codes, you can enter the hex code that you want repeated, OR a link to a file to read the byte string from. The cargo space for the packet will be padded with this data. Use this in conjunction with the packet size to create the network scenario you're looking to duplicate.

