Traceroute

To find the way information packets follow when reaching a host, use traceroute utility (named tracert.exe in Windows). To start using it, open cmd.exe (command prompt, use “Run as Administrator”) and issue command like

tracert google.com

Below typical output from tracert is shown:

tracert to google.com

Every line (also called a “hop”) relates to a router passed while reaching the target host. Number of hops (also known as “hop limit” or TTL, “time to live”, value) can be altered by using “-h” command parameter; it defaults to 30.

The data per line: hop number, three “round trip” times, namely time between ICMP Echo sent to router and response received; tracert.exe uses three packets and prints three results. The last line is router host name (if its address is resolved to DNS name) or IP address otherwise.

tracert.exe sends packets, increasing their TTL, until either host is contacted, or hop limit is reached. If host has been contacted and responded, “Trace complete” is displayed, meaning the tracing ended successfully. Round trip times provide information on slowest parts if the route, and average time required to reach the host.

You can see lines with asterisks instead of round trip times, and “Request timed out” line instead of host name/IP. These routers either refuse to respond to ICMP pakcets sent, or exhibit other connectivity issues.

Below is an example of output when host name can’t be resolved to IP address.

tracert to google.com

Below is an example when 30 hops is insufficient to complete the traceroute.

tracert to google.com

tracert.exe is a basic network analysis tool; it can be used to quickly detect network problem resulting in lost connectivity. Please refer to tracert.exe manual pages for more information.

Glossary

IPHost features:

PING Monitoring: IPHost Network Monitor is a powerful IP monitoring tool for automatic checking of connection to network hosts. Tool monitors network connections by making regular PINGs and it sends alerts when states of some equipment change. Download IPHost Network Monitor and in less than 5 minutes you will be able to monitor your network 24/7 and get timely alerts on networking issues before they become a disaster.

PING: Internet Control Message Protocol, or ICMP, is one of the protocols used to pass diagnostic messages between network devices. For example, if there’s problem locating the target network device we are trying to connect to, an ICMP message can be sent to indicate the error. There are but few programs utilizing ICMP, one of them being ping utility.

You can use Traceroute to check connectivity to host, along with PING monitors.


IPHost Network Monitor 5.3 build 14150 of December 25, 2020. File size: 68MB