Autotrace

Description

AutoTrace is an Enhanced Service, and is only available to use in conjunction with Secure Device (https) monitoring.

If you have activated AutoTrace for a particular monitored device, then when Red Alert detects a potentially network-related problem when attempting to access that device, it conducts a traceroute to that device via each of the Red Alert Monitoring Networks. The results are stored at the Red Alert site for your examination. When Red Alert later finds that your device is OK again, it conducts another set of traceroutes and stores the results, so you may compare how the routes to your device appeared during the problem and after the problem was resolved.

When traceroutes have been conducted, the results are stored at a certain URL at the Red Alert site. Your account's username and password must be provided in order to access this information. The URL appears in two places:

Traceroute is a standard network diagnostic tool which shows the routers on the path of connectivity between two Internet sites. For example, the following is the result of a traceroute from Red Alert's site to the White House's site, via one of the Red Alert Monitoring Networks:

 
1  gate0.redalert.com       (207.55.188.11)   2.32 ms  2.275 ms  2.346 ms  
2  redalert.nkn.net         (204.214.9.197)   7.946 ms  8.123 ms  8.156 ms  
3  nkn.dfw.verio.net        (205.238.52.101)  8.388 ms  8.242 ms  8.446 ms  
4  dfw.mae-west.verio.net   (205.238.56.21)  41.279 ms  41.366 ms  41.333 ms  
5  mae-west2.us.psi.net     (198.32.184.23)  42.266 ms  41.176 ms  43.56 ms  
6  se.sc.psi.net            (38.1.3.5)       91.881 ms  121.74 ms  91.671 ms  
7  rc5.southeast.us.psi.net (38.1.25.5)      96.864 ms  96.158 ms  104.053 ms  
8  ip2.ci3.herndon.va.us.psi.net (38.25.11.2)  98.392 ms  96.268 ms  99.557 ms  
9  198.137.240.33           (198.137.240.33) 95.278 ms  96.926 ms  95.053 ms 
10  www2.whitehouse.gov      (198.137.240.92) 97.04 ms  94.896 ms  95.896 ms
Each of the "hops" numbered 1 through 9 represents an Internet router, while the machine at hop 10 is one of the White House's Web servers. If the router at hop 9 were down for some reason, the end of the traceroute results might instead appear as follows:
 
6  se.sc.psi.net            (38.1.3.5)       91.881 ms  121.74 ms  91.671 ms  
7  rc5.southeast.us.psi.net (38.1.25.5)      96.864 ms  96.158 ms  104.053 ms  
8  ip2.ci3.herndon.va.us.psi.net (38.25.11.2)  98.392 ms  96.268 ms  99.557 ms  
9  *  *  * 10  *  *  * 11  *  *  * 12  *  *  *    (etc.)
An asterisk ( * ) represents a point at which one of the traceroute "probe" packets was not echoed, indicating possible packet loss at that hop.

Traceroute can be extremely useful in tracking down the point at which connectivity to your Internet device has been interrupted. With AutoTrace activated, you will have traceroute results taken via multiple independent networks at exactly the times when you need them.


How to Use

When adding a new device for monitoring, you will be asked whether you wish to activate AutoTrace for that device.

To activate this service for an existing device, click the "Enable AutoTrace" link under the actions for a secure URL device.

To deactivate this service, click the "Disable AutoTrace" link under the actions for a secure URL device.


Troubleshooting

Traceroute is an invaluable diagnostic tool, but it does have some limitations to be aware of:

  • Some firewalls block traceroute probes, resulting in only asterisks for all hops beyond the firewall. Therefore, before concluding that the presence of asterisks at a particular hop indicates a problem, you should know whether traceroute probes normally are able to reach that point.
  • In some cases, the Internet route from site A to site B is different from the return route from site B to site A. This is known as asymmetric routing. There is nothing inherently wrong with asymmetric routing, but it can cause misleading traceroute results. A problem may appear to be located at a certain hop on the route from A to B even though the actual problem is at a hop on the return route from B to A which does not appear in the traceroute results at all. (But note that Red Alert's use of multiple independent networks greatly reduces the number of cases in which asymmetric routing can cause misleading traceroute results.)
For these reasons, traceroute should be viewed as a tool for providing diagnostic data, rather than as an authoritative source for diagnosis of network problems.