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Packet Loss Test (Line Quality)

Add ny-monitor.dslreports.com - This is our New York server.
This takes care of the Security Scan, the Tweaks Test Applet and the East Coast Line Quality Test server.

Add sfo-monitor.dslreports.com - This is our San Francisco server.

Add sjc-monitor.dslreports.com - This is our San Jose server.

You should add those three domains to a "friendly" (local) zone with a lower protection rating.
Zone Alarm users click here for instructions.

Zone Alarm Pro users:
To become pingable, click Security > Customize (Internet side) > check off "Allow incoming ping (ICMP echo)." Click Apply then Ok. This will allow your machine to be totally pingable.

Feedback received on this FAQ entry:
  • As noted in http://www.dslreports.com/faq/329 sjc-monitor.dslreports.com is no longer available.

    2015-01-07 13:07:19 (aefstoggaflm See Profile)

by Mike See Profile edited by JMGullett See Profile
last modified: 2007-04-26 16:32:48

When you use tool points to pay for a priority line quality test, your test is recorded as priority -- meaning, you're next in line when the queue processor picks a test to do. You just have to wait a few minutes for the test that's currently underway to be completed. During that time, it will look as if you've been placed at the end of the queue.
You really will be queue-jumping, but not until whatever is being processed at that moment is completed.

by KeysCapt See Profile edited by JMGullett See Profile
last modified: 2007-04-26 16:42:17

You need to be pingable since the test results can show accurate latency (ping time) for your connection. Your firewall or router prevents pings from being responded to, if properly set. If you're not pingable, the test will show a 100% loss at your address for both coasts.

If you're using a router, set it to allow pings. If you're using a firewall, the quickest way to become pingable is to tone down on the security level or just turn it off for the duration of the test. Some firewalls have an option to add IPs into a local or trusted zone that will give this IP more access than the general pool. These are the IP addresses that do the Monitor / Line Quality work.

Reason to be pingable:
This allows you to see if there are congestion problems, bottlenecks, bad routers and/or if something is wrong at your location. If you're not pingable, the only thing the test is useful for is a fancy traceroute.

by Skipdawg See Profile edited by JMGullett See Profile
last modified: 2007-04-26 16:48:02

This is often a sign of an unpingable router. Your packets are being routed correctly to and from the router, but we cannot ping it. The network engineers probably made the router itself unpingable. Some ISPs and backbones make their routers unpingable to minimize "wasted" bandwidth.

by Skipdawg See Profile edited by JMGullett See Profile
last modified: 2007-04-26 16:52:39

You're using a Qwest/MSN-provided Alcatel CPE. There is nothing you can do about it.


There is an issue with your current network configuration.

Go back to the Desktop, right click on "Network Neighborhood" - "Properties." The Network Configuration window should pop up. In the white box, check for any duplicate TCP/IP or any duplicate hardware adapters. Leave only one and delete any extras. Reboot. You should run another Line Quality test to see if the problem persists. It shouldn't, but it's always good to check.

Another thing for Windows users to do is to have your NIC (ethernet card) installation disk handy, load into Windows Safe Mode, delete all the hardware adapters and start from scratch.

If you do not know how to enter into safe mode and make changes, just start a new topic asking for assistance in our Microsoft Help Forum.

by Mike See Profile edited by JMGullett See Profile
last modified: 2007-04-26 17:03:17

This option is not available at this time. Once you are in the queue, you can not be removed from it.

by Mike See Profile edited by JMGullett See Profile
last modified: 2007-04-26 17:10:01

1. Host LOSS - This indicates the percentage of packets dropped by that particular router.

2. Best - Lowest ping to the router
Avg. - Average ping to the router
Worst - Highest ping to the router

The lower the ping, the better.

3. Gateway - The second to the last hop is your gateway. The gateway is a node on a network that serves as a entrance for local users onto the ISPs network.

4. (YOUR ADDRESS) - This is your computer. A dropped packet (shows as 2% dropped) loss is very common with an ICMP stream.

by redxii See Profile edited by JMGullett See Profile
last modified: 2007-04-26 17:11:55

It's possible that there is something wrong with your setup. Here are a few things that you can do to possibly fix the problem:

- Make sure that your modem is at least 12 inches (roughly 30 centimeters) clear of anything that emits electromagnetic interference (such as a CRT monitor). Make sure that all cables are not physically damaged and are properly connected. Halogen lighting and light dimmers in proximity to the computer can also cause a problem.

- Ensure that your ethernet card is seated properly and that your drivers are up to date.

- Reset your modem. Unplug it for about a minute or two, then plug it back in and let it regain sync.

If none of the above correct the issue, it would be in your best interest to contact your ISP and have them do an inspection of the line itself.

by blueschooner See Profile edited by JMGullett See Profile
last modified: 2007-04-26 17:13:34

If you see a "Host Precedence Violation" on your Line Quality test results page accompanied by a really high reported gateway ping, don't panic!

Here's the technical definition for a Host Precedence Violation (under RFC-1812): "Sent by the first hop router to a host to indicate that a requested precedence is not permitted for the particular combination of source/destination host or network, upper layer protocol and source/destination port."

Keep in mind, this is just a reference; there is a much-easier-to-digest explanation.

Let's go back to your Test History page. Find a Line Quality test then open it. Go down and look at the "your first hop ping" row. Check your gateway's IP. Most likely, it is between &, & or &, correct?

Those three domain ranges are in something dubbed the "Private IP Network" domains. With the way the Internet works, your ISP has set up an "exclusive LAN." Your ISP has your gateway set up so that it is dedicated to only Internet traffic coming from you and going to you. The DSLreports servers are not recognized within your ISP's network, so your gateway doesn't respond to any packets being sent directly to it. Your first hop ping is then estimated. Nearly all of the time, it shows up as way higher than it really is.

Do you want to know what your first hop ping really is?

With your Windows PC, go to "Start" - "Run" - then type "ping -t Your Gateway's IP here."

With your Mac OS X PC, open Terminal and type "ping IP here."

Open the Network Utility and fill in the text box.

With your Linux PC, go to a shell, then type "ping Your Gateway's IP here."

Since the gateway recognizes you as a part of your ISP's "happy family," it will correctly respond to a ping and return accurate results.

by Mike See Profile edited by JMGullett See Profile
last modified: 2007-05-07 12:02:55

The router watch list is formed by sweeping the individual line quality tests done over the last three weeks so we can compile a list of Internet routers that were discovered to be the source of packet loss. The only way to be added is to be a bad router.

If you really want to be added, we recommend beating your main switch with a herring.*

*Please be nice to routing equipment and the herring.

Feedback received on this FAQ entry:
  • WOW, I love this AWESOME site!! Please consider putting (at some future time) links to the test (or whatever the faq is about) in question so that one may simply click on it to see the test startup page and perhaps perform the test. (Links in blue type or some other color.) This would likely apply to all faq items. Thanks, GlennNDavis@fuse.net

    2011-12-24 11:34:29

by Mike See Profile edited by JMGullett See Profile
last modified: 2007-04-26 17:15:21

If you are also seeing packet loss from these points all the way to the final hop of your test, that points to a problem on the device first showing packet loss or on the inbound connection to that device.

However, if you are not seeing packet loss all the way to the final hop, this apparent packet loss may not be an issue.

Some providers are rate-limiting how often they respond with the TTL-exceeded ICMP packets used by traceroute and similar tools like the Packet Loss Test. This is done to prevent attacks against these routers, since responding to these packets requires much more CPU time than simply forwarding the packet does. If the router is set up to rate-limit, it will respond to a certain number of traceroute packets per second, and once that many have been received, it will stop responding to them for that second -- which will appear as packet loss. You are not losing any "real" traffic, assuming the final hop of your traceroute isn't showing any loss.

by Xyc See Profile edited by JMGullett See Profile
last modified: 2007-04-26 17:18:05