Ports and Protocols
Port # |
Acronym |
Protocol |
Transport Layer Protocol |
Notes |
7 |
echo |
echo, ping |
TCP, UDP |
Port echoes whatever is sent to it |
20 |
FTP |
File Transfer Protocol |
TCP |
Data transfer |
21 |
FTP |
File Transfer Protocol |
TCP |
Control command |
22 |
SSH |
Secure Shell |
TCP, UDP |
Secure logins, file transfers (SCP, SFTP), and port forwarding |
23 |
TELNET |
TELNET |
TCP |
Unencrypted text communications |
25 |
SMTP |
Simple Mail Transfer Protocol |
TCP |
Used for email routing between mail servers |
49 |
TACACS+ |
TACACS+ Login Host Protocol |
TCP, UDP |
|
53 |
DNS |
Domain Name System |
TCP, UDP |
|
67 |
DHCP |
Dynamic Host Configuration Protocol |
UDP |
and BOOTP (Bootstrap protocol) server |
68 |
DHCP |
Dynamic Host Configuration Protocol |
UDP |
and BOOTP (Bootstrap protocol) client |
69 |
TFTP |
Trivial File Transfer Protocol |
UDP |
|
80 |
HTTP |
Hypertext Transfer Protocol |
TCP, UDP |
Web server communication |
88 |
Kerberos |
Kerberos |
TCP |
Authentication system |
110 |
POP3 |
Post Office Protocol version 3 |
TCP |
Receive email into an email client |
119 |
NNTP |
Network News Transfer Protocol |
TCP |
Retrieval of news group messages |
123 |
NTP |
Network Time Protocol |
UDP |
Used for time synchronization |
137 |
NetBIOS |
NetBIOS Name Service |
UDP |
Register, remove, and find services by name |
138 |
NetBIOS |
NetBIOS Datagram Service |
UDP |
Connectionless data transfer |
139 |
NetBIOS |
NetBIOS Session Service |
TCP |
Connection-oriented data transfer |
143 |
IMAP4 |
Internet Mail Access Protocol version 4 |
TCP |
Management of electronic mail messages on a server. Newer email client protocol. |
161 |
SNMP |
Simple Network Management Protocol |
UDP |
SNMP Agent receives requests on UDP port 161. |
162 |
SNMP |
Simple Network Management Protocol |
UDP |
SNMP Management station receives SNMP notifications on UDP port 162. |
389 |
LDAP |
Lightweight Directory Access Protocol |
TCP |
Internet protocol used by MS Active Directory as well as some email programs to look up contact info from a server. |
443 |
HTTPS |
Hypertext Transfer Protocol Secure |
TCP |
Secure web browser communication. SSL over VPN or HTTP over TLS/SSL. Encrypted. |
445 |
SMB |
Server Message Block |
TCP |
Used for file sharing in Windows NT/2K/XP and direct TCP/IP MS Networking access without the need for a NetBIOS layer. |
500 |
Ipsec |
Internet Protocol security |
UDP |
Through the use of ISAKMP (Internet Security Association and Key Management Protocol) |
514 |
Syslog |
System Logging |
UDP |
Used for system logging |
1701 |
L2TP |
Layer 2 Tunneling Protocol |
UDP |
|
1720 |
H.323 |
H.323 |
TCP |
(VoIP) call signalling protocol during call setup negotiation. Most common in Microsoft NetMeeting. For media content streaming. |
1723 |
PPTP |
Point-to-Point Tunneling Protocol |
TCP |
|
1812 |
RADIUS - Authentication |
RADIUS Authentication Protocol |
TCP, UDP |
|
1813 |
RADIUS - Accounting |
RADIUS Accounting Protocol |
TCP, UDP |
|
2427 |
MGCP |
Media Gateway Control Protocol - Gateway |
UDP |
Call Agent to Gateway |
2727 |
MGCP |
Media Gateway Control Protocol - Call Agent |
TCP, UDP |
Gateway to Call Agent. Media Gateway Controller (call agent). |
3389 |
RDP |
Remote Desktop Protocol |
TCP, UDP |
Microsoft Terminal Server (RDP) officially registered as Windows Based Terminal (WBT). |
5004 |
RTP |
Real-time Transport Protocol |
UDP |
VoIP media stream. Media data. |
5005 |
RTCP |
Real-time Transport Control Protocol |
UDP |
VoIP media stream. |
5060 |
SIP |
Session Initiation Protocol |
TCP, UDP |
VoIP signaling. Non-encrypted traffic. |
5061 |
SIP over TLS |
Session Initiation Protocol over TLS |
TCP |
VoIP signaling. Traffic encrypted with TLS. |
Commands
Command |
Switch |
What it does |
Troubleshooting examples |
arp |
-a -d -g -N -s -v |
Computers use the Address Resolution Protocol (ARP) to resolve IP addresses to MAC addresses. As the computer learns various MAC addresses on its LAN, it jots them down in the ARP table. When Computer A wants to send a message to Computer B, it determines B's IP address and then checks the ARP table for a corresponding MAC address. Displays the current entries in the Address Resolution Protocol (ARP) table. |
What can you use to verify an IP address conflict on a network? If a host is reachable from one workstation but not from another, you can use the arp command on both workstations to display the current entries in the ARP table. If the MAC address on the problem workstation does not match the correct MAC address, you can use arp to delete the incorrect entry. Can be used with ping for more complex network problems. |
arp |
-a |
Displays ARP table: all current ARP entries for all interfaces. IP address, MAC address, Type (dynamic or static). What your computer uses when it has the IP address but needs to know the MAC address. |
How to see Windows' current ARP table? |
arp |
-d |
Deletes the host specified by inet_addr. inet_addr may be wildcarded with * to delete all hosts. |
Value |
arp |
-g |
Displays all the current ARP entries for all interfaces. Same as -a |
|
arp |
-N <interface IP address> |
Lists all ARP entries for the interface specified. |
|
arp |
-s <MAC address> |
Adds a static entry to the ARP cache. |
|
arp |
-v |
Displays current ARP entries in verbose mode (option that provides additional details as to what the computer is doing and what drivers and software it is loading during startup). All invalid entries and entries on the loop-back interface will be shown. |
|
dig |
<domain.com> A <domain.com> MX <domain.com> NS <domain.com> ANY |
Domain Information Groper. Used to query and verify DNS functionality / diagnose DNS problems. |
DNS lookups of a certain host are not always successful. What tool can you use to verify this problem? dig ...is used to query DNS name servers |
dig |
<domain.com> A |
Gets the IP address for domain.com |
|
dig |
<domain.com> MX |
Get a list of all the mailservers for domain.com |
|
dig |
<domain.com> NS |
Get a list of authoritative DNS servers (name servers) for domain.com |
|
dig |
<domain.com> ANY |
Get a list of the IP address, mailservers, and authoritative DNS servers for domain.com |
|
hostname |
Command that returns with the name of the computer you are on. |
||
ifconfig |
"Interface Configuration" is a very important utility of Linux systems. It is used to check & configure network interfaces using the terminal or CLI of Linux machines. Can check information regarding the network interfaces, configure them or enable and disable them. |
||
ipconfig |
/all /displaydns /flushdns /release /release6 /renew /renew6 /registerdns /setclassid /setclassid6 /showclassid /showclassid6 |
Displays TCP/IP configuration information. Provides network info for each network adapter. Also displays connection-specific DNS suffix, IP address, subnet mask, and default gateway information. |
|
ipconfig |
/all |
Displays full configuration information. Provides detailed network information for each network adapter, such as DNS server IP addresses, DHCP lease information, MAC address, and adapter hardware description. |
|
ipconfig |
/displaydns |
Display the contents of the DNS Resolver cache. |
|
ipconfig |
/flushdns |
Purges the DNS Resolver cache. |
|
ipconfig |
release |
Release the IPv4 address for the specified adapter. |
|
ipconfig |
/release6 |
Release the IPv6 address for the specified adapter. |
|
ipconfig |
/renew |
Renew the IPv4 address for the specified adapter. |
|
ipconfig |
/renew6 |
Renew the IPv6 address for the specified adapter. |
|
ipconfig |
/registerdns |
Refreshes all DHCP leases and re-registers DNS names. |
|
ipconfig |
/setclassid |
Modifies the dhcp class id. |
|
ipconfig |
/setclassid6 |
Modifies the IPv6 DHCP class id. |
|
ipconfig |
/showclassid |
Displays all the dhcp class IDs allowed for adapter. |
|
ipconfig |
/showclassid6 |
Modifies the IPv6 DHCP class id. |
|
mtr |
My Traceroute is a dynamic (keeps running) equivalent to traceroute. Windows does not support mtr. |
||
nbtstat |
-a -A -c -n -r -R -S -s -RR |
A Windows-only program that can best be described as a command-line pseudo-equivalent to Window's My Network Places or Network icon. Always run it with a switch. nbtstat will display the contents of the NetBIOS names cache. |
|
nbtstat |
-a |
(adapter status) Lists the remote machine's name table given its name. |
|
nbtstat |
-A |
(Adapter status) Lists the remote machine's name table given its IP address. |
|
nbtstat |
-c |
(cache) Lists NBT's cache of remote [machine] names and their IP addresses. |
|
nbtstat |
-n |
(names) Shows the local NetBIOS names. Handy way to see what systems are on your Windows network. |
|
nbtstat |
-r |
(resolved) Lists names resolved by broadcast and via WINS. |
|
nbtstat |
-R |
(Reload) Purges and reloads the remote cache name table. |
|
nbtstat |
-S |
(Sessions) Lists sessions table with the destination IP addresses. |
|
nbtstat |
-s |
(sessions) Lists sessions table converting destination IP addresses to computer NetBIOS names. |
|
nbtstat |
-RR |
(Release Refresh) Sends Name Release packets to WINS and then, starts Refresh. |
|
netstat |
-a -e -n -o -p -r -s [interval] |
Network status. Displays info on the current state of all of your running IP processes. It shows what sessions are active and can also provide statistics based on ports or protocols (TCP, UDP, and so on). Shows listing of open TCP connections and network statistics for specific protocols. Displays a list of network services, connection information, and statuses. Shows the status of each active network connection. Displays statistics for both TCP and UDP, including protocol, local address, foreign address, and the TCP connection state. |
|
netstat |
-a |
||
Value |
|||
Example Outputs of Commands
Arp
Computers use the Address Resolution Protocol (ARP) to resolve IP addresses to MAC addresses. As the computer learns various MAC addresses on its LAN, it jots them down in the ARP table. When Computer A wants to send a message to Computer B, it determines B's IP address and then checks the ARP table for a corresponding MAC address.
The CompTIA Network+ exam objectives refer to the ARP table as the mac address lookup table.
The CompTIA Network+ exam objectives refer to the ARP table as the mac address lookup table.
More info at https://technet.microsoft.com/en-us/library/cc940107.aspx
Arp allows you to view and modify the ARP cache. If two hosts on the same subnet cannot ping each other successfully, try running the arp -a command on each computer to see whether the computers have the correct media access control (MAC) addresses listed for each other. You can use Ipconfig to determine a host's correct MAC address.
You can also use Arp to view the contents of the ARP cache by typing arp -a at a command prompt. This displays a list of the ARP cache entries, including their MAC addresses. Following is an example list of ARP cache entries.
C:\>arp -a
Interface: 172.16.0.142 on Interface 0x2
Internet address Physical Address Type
172.16.0.1 00-e0-34-c0-a1-40 dynamic
172.16.1.231 00-00-f8-03-6d-65 dynamic
172.16.3.34 08-00-09-dc-82-4a dynamic
172.16.4.53 00-c0-4f-79-49-2b dynamic
172.16.5.102 00-00-f8-03-6c-30 dynamic
If another host with a duplicate IP address exists on the network, the ARP cache might have the MAC address for the other computer placed in it, and this can lead to intermittent problems with address resolution. When a computer on the local network sends an ARP Request to resolve the address, it forwards its data to the MAC address corresponding to the first ARP Reply it receives. Arp can help by listing, adding, and removing the relevant entries.
You can use arp -d < IP address > to delete incorrect entries. Use arp -s < MAC address > (where the MAC address is formatted as hexadecimal bytes separated by dashes) to add new static entries; these static entries do not expire from the ARP cache. However, static entries do not persist after a reboot. For persistent static ARP cache entries, you must create a batch file run from the Startup group.
Use arp -N < IP address > to list all the ARP entries for the network interface specified by < IP address>. Table 3.2 lists all Arp switches.
Table 3.2 Arp Switches
Arp allows you to view and modify the ARP cache. If two hosts on the same subnet cannot ping each other successfully, try running the arp -a command on each computer to see whether the computers have the correct media access control (MAC) addresses listed for each other. You can use Ipconfig to determine a host's correct MAC address.
You can also use Arp to view the contents of the ARP cache by typing arp -a at a command prompt. This displays a list of the ARP cache entries, including their MAC addresses. Following is an example list of ARP cache entries.
C:\>arp -a
Interface: 172.16.0.142 on Interface 0x2
Internet address Physical Address Type
172.16.0.1 00-e0-34-c0-a1-40 dynamic
172.16.1.231 00-00-f8-03-6d-65 dynamic
172.16.3.34 08-00-09-dc-82-4a dynamic
172.16.4.53 00-c0-4f-79-49-2b dynamic
172.16.5.102 00-00-f8-03-6c-30 dynamic
If another host with a duplicate IP address exists on the network, the ARP cache might have the MAC address for the other computer placed in it, and this can lead to intermittent problems with address resolution. When a computer on the local network sends an ARP Request to resolve the address, it forwards its data to the MAC address corresponding to the first ARP Reply it receives. Arp can help by listing, adding, and removing the relevant entries.
You can use arp -d < IP address > to delete incorrect entries. Use arp -s < MAC address > (where the MAC address is formatted as hexadecimal bytes separated by dashes) to add new static entries; these static entries do not expire from the ARP cache. However, static entries do not persist after a reboot. For persistent static ARP cache entries, you must create a batch file run from the Startup group.
Use arp -N < IP address > to list all the ARP entries for the network interface specified by < IP address>. Table 3.2 lists all Arp switches.
Table 3.2 Arp Switches
Switch |
Name |
Effect |
-d < IP address > |
Delete |
Removes the listed entry from the ARP cache |
-s < MAC address > |
Static |
Adds a static entry to the ARP cache |
-N < interface IP address > |
Interface |
Lists all ARP entries for the interface specified |
-a |
Display |
Displays all the current ARP entries for all interfaces |
-g |
Display |
Displays all the current ARP entries for all interfaces |
Dig
Dig (on Mac OS X and Linux) and nslookup (on Microsoft Windows) are the primary command-line tools for troubleshooting DNS issues.
Top 10 Basic Network Troubleshooting Tools Every IT Pro Should Know
https://www.pluralsight.com/blog/it-ops/network-troubleshooting-tools
Network troubleshooting tools are a necessity for every network administrator. When getting started in the networking field, it is important to amass a number of tools that can be used to troubleshoot a variety of different network conditions.While it is true that the the use of specific tools can be subjective and at the discretion of the engineer, the selection of tools in this article has been made based on their generality and common use. This article reviews the top 10 basic tools that can help you troubleshoot most networking issues.
10. Ping
The most commonly used network tool is the ping utility. This utility is used to provide a basic connectivity test between the requesting host and a destination host. This is done by using the Internet Control Message Protocol (ICMP) which has the ability to send an echo packet to a destination host and a mechanism to listen for a response from this host. Simply stated, if the requesting host receives a response from the destination host, this host is reachable. This utility is commonly used to provide a basic picture of where a specific networking problem may exist. For example, if an Internet connection is down at an office, the ping utility can be used to figure out whether the problem exists within the office or within the network of the Internet provider. Figure 1 below shows an example of the ping utility being used to obtain the reachability status of the locally connected router.
Figure 1: Ping utility
9. Tracert/traceroute
Typically, once the ping utility has been used to determine basic connectivity, the tracert/traceroute utility can used to determine more specific information about the path to the destination host including the route the packet takes and the response time of these intermediate hosts. Figure 2 below shows an example of the tracert utility being used to find the path from a host inside an office to www.google.com. The tracert utility and traceroute utilities perform the same function but operate on different operating systems, Tracert for Windows machines and traceroute for Linux/*nix based machines.
Figure 2: Tracert/traceroute utility
8. Ipconfig/ifconfig
One of the most important things that must be completed when troubleshooting a networking issue is to find out the specific IP configuration of the variously affected hosts. Sometimes this information is already known when addressing is configured statically, but when a dynamic addressing method is used, the IP address of each host can potentially change often. The utilities that can be used to find out this IP configuration information include the ipconfig utility on Windows machines and the ifconfig utility on Linux/*nix based machines. Figure 3 below shows an example of the ifconfig utility showing the IP configuration information of a queries host.
Figure 3: Ifconfig utility
7. Nslookup
Some of the most common networking issues revolve around issues with Dynamic Name System (DNS) address resolution issues. DNS is used by everyone using the Internet to resolve commonly known domain names (i.e. google.com) to commonly unknown IP addresses (i.e. 74.125.115.147). When this system does not work, most of the functionality that people are used to goes away, as there is no way to resolve this information. The nslookup utility can be used to lookup the specific IP address(es) associated with a domain name. If this utility is unable to resolve this information, there is a DNS issue. Along with simple lookup, the nslookup utility is able to query specific DNS servers to determine an issue with the default DNS servers configured on a host. Figure 4 below shows an example of how the nslookup utility can be used to query the associated IP address information.
Figure 4: Nslookup utility
6. Netstat
Often, one of the things that are required to be figured out is the current state of the active network connections on a host. This is very important information to find for a variety of reasons. For example, when verifying the status of a listening port on a host or to check and see what remote hosts are connected to a local host on a specific port. It is also possible to use the netstat utility to determine which services on a host that is associated with specific active ports. Figure 5 below shows an example of the netstat utility being used to display the currently active ports on a Linux machine.
Figure 5: Netstat utility
5. PuTTY/Tera Term
When connecting to a variety of different types of equipment, a telnet, SSH or serial client is required; when this is required both the puTTY and Tera Term programs are able to provide these functionalities. The selection of one over the other is strictly a personal preference. Figures 6 and 7 below show both puTTY and Tera Term being used to connect to a host via SSH.
Figure 6: PuTTY
Figure 7: Tera Term
4. Subnet and IP Calculator
One of the most important tools in the belt of a junior network engineer is an IP network calculator. These can be used to unsure a correct IP address selection and with this a correct IP address configuration. While this type of tool is used by senior level network engineers, much of the information obtained from the tool becomes simpler to calculate the longer and more experience you have in the field. Two of the more commonly used free IP calculators include Wildpackets (Bitcricket) Network Calculator and Solarwinds Advanced Subnet Calculator which can be found at the links below.
http://www.bitcricket.com/downloads/IPCalculator.msi
http://downloads.solarwinds.com/solarwinds/Release/FreeTool/SolarWinds-Subnet-Calculator.zip
Figure 8: Subnet calculator
3. Speedtest.net/pingtest.net
A very easy test that can be used to both determine the Internet bandwidth available to a specific host and to determine the quality of an Internet connection is the use of the tools available at the speedtest.net and pingtest.net websites. The speedtest.net site provides the ability to determine the amount of bandwidth that is available to a specific host at a specific point in time; this is often a good tool to use when measuring how long it is going to take to upload or download information from a local to remote host. This measurement can also be used to determine whether the connection is offering the amount of bandwidth that was purchased from the Internet provider; keep in mind however that some amount of bandwidth difference is expected between the quoted bandwidth purchased and the measured bandwidth. The pingtest.net website is used to determine the quality of the connection by measuring the ping response times and jitter amounts over a short period of time. This information can be used to determine a likelihood of how well the measured connection will deal with certain types of high demand traffic like Voice over IP (VoIP) or gaming. Figure 9 and 10 below show example output from both of these sites.
Figure 9: Speedtest
Figure 10: Pingtest
2. Pathping/mtr
In an effort to take advantage of the benefits of both the ping and tracert/traceroute commands, the pathping and mtr utilities were developed. Both of these tools take the functionality and information that can be obtained from these types of tools and provide a more detailed single picture of the path characteristics from a specific host to a specific destination. Figure 11 and 12 below show examples of these two tools and what information they provide.
Figure 11: Pathping
Figure 12: Mtr
1. Route
The last of the tools covered in this article is the route utility. This utility is used to display the current status of the routing table on a host. While the use of the route utility is limited in common situations where the host only has a single IP address with a single gateway, it is vital in other situations where multiple IP address and multiple gateways are available. Figure 13 below shows an example of the route utility being used on a Windows machine.
Figure 13: Route Utility
Network troubleshooting tools are a necessity for every network administrator. When getting started in the networking field, it is important to amass a number of tools that can be used to troubleshoot a variety of different network conditions.While it is true that the the use of specific tools can be subjective and at the discretion of the engineer, the selection of tools in this article has been made based on their generality and common use. This article reviews the top 10 basic tools that can help you troubleshoot most networking issues.
10. Ping
The most commonly used network tool is the ping utility. This utility is used to provide a basic connectivity test between the requesting host and a destination host. This is done by using the Internet Control Message Protocol (ICMP) which has the ability to send an echo packet to a destination host and a mechanism to listen for a response from this host. Simply stated, if the requesting host receives a response from the destination host, this host is reachable. This utility is commonly used to provide a basic picture of where a specific networking problem may exist. For example, if an Internet connection is down at an office, the ping utility can be used to figure out whether the problem exists within the office or within the network of the Internet provider. Figure 1 below shows an example of the ping utility being used to obtain the reachability status of the locally connected router.
Figure 1: Ping utility
9. Tracert/traceroute
Typically, once the ping utility has been used to determine basic connectivity, the tracert/traceroute utility can used to determine more specific information about the path to the destination host including the route the packet takes and the response time of these intermediate hosts. Figure 2 below shows an example of the tracert utility being used to find the path from a host inside an office to www.google.com. The tracert utility and traceroute utilities perform the same function but operate on different operating systems, Tracert for Windows machines and traceroute for Linux/*nix based machines.
Figure 2: Tracert/traceroute utility
8. Ipconfig/ifconfig
One of the most important things that must be completed when troubleshooting a networking issue is to find out the specific IP configuration of the variously affected hosts. Sometimes this information is already known when addressing is configured statically, but when a dynamic addressing method is used, the IP address of each host can potentially change often. The utilities that can be used to find out this IP configuration information include the ipconfig utility on Windows machines and the ifconfig utility on Linux/*nix based machines. Figure 3 below shows an example of the ifconfig utility showing the IP configuration information of a queries host.
Figure 3: Ifconfig utility
7. Nslookup
Some of the most common networking issues revolve around issues with Dynamic Name System (DNS) address resolution issues. DNS is used by everyone using the Internet to resolve commonly known domain names (i.e. google.com) to commonly unknown IP addresses (i.e. 74.125.115.147). When this system does not work, most of the functionality that people are used to goes away, as there is no way to resolve this information. The nslookup utility can be used to lookup the specific IP address(es) associated with a domain name. If this utility is unable to resolve this information, there is a DNS issue. Along with simple lookup, the nslookup utility is able to query specific DNS servers to determine an issue with the default DNS servers configured on a host. Figure 4 below shows an example of how the nslookup utility can be used to query the associated IP address information.
Figure 4: Nslookup utility
6. Netstat
Often, one of the things that are required to be figured out is the current state of the active network connections on a host. This is very important information to find for a variety of reasons. For example, when verifying the status of a listening port on a host or to check and see what remote hosts are connected to a local host on a specific port. It is also possible to use the netstat utility to determine which services on a host that is associated with specific active ports. Figure 5 below shows an example of the netstat utility being used to display the currently active ports on a Linux machine.
Figure 5: Netstat utility
5. PuTTY/Tera Term
When connecting to a variety of different types of equipment, a telnet, SSH or serial client is required; when this is required both the puTTY and Tera Term programs are able to provide these functionalities. The selection of one over the other is strictly a personal preference. Figures 6 and 7 below show both puTTY and Tera Term being used to connect to a host via SSH.
Figure 6: PuTTY
Figure 7: Tera Term
4. Subnet and IP Calculator
One of the most important tools in the belt of a junior network engineer is an IP network calculator. These can be used to unsure a correct IP address selection and with this a correct IP address configuration. While this type of tool is used by senior level network engineers, much of the information obtained from the tool becomes simpler to calculate the longer and more experience you have in the field. Two of the more commonly used free IP calculators include Wildpackets (Bitcricket) Network Calculator and Solarwinds Advanced Subnet Calculator which can be found at the links below.
http://www.bitcricket.com/downloads/IPCalculator.msi
http://downloads.solarwinds.com/solarwinds/Release/FreeTool/SolarWinds-Subnet-Calculator.zip
Figure 8: Subnet calculator
3. Speedtest.net/pingtest.net
A very easy test that can be used to both determine the Internet bandwidth available to a specific host and to determine the quality of an Internet connection is the use of the tools available at the speedtest.net and pingtest.net websites. The speedtest.net site provides the ability to determine the amount of bandwidth that is available to a specific host at a specific point in time; this is often a good tool to use when measuring how long it is going to take to upload or download information from a local to remote host. This measurement can also be used to determine whether the connection is offering the amount of bandwidth that was purchased from the Internet provider; keep in mind however that some amount of bandwidth difference is expected between the quoted bandwidth purchased and the measured bandwidth. The pingtest.net website is used to determine the quality of the connection by measuring the ping response times and jitter amounts over a short period of time. This information can be used to determine a likelihood of how well the measured connection will deal with certain types of high demand traffic like Voice over IP (VoIP) or gaming. Figure 9 and 10 below show example output from both of these sites.
Figure 9: Speedtest
Figure 10: Pingtest
2. Pathping/mtr
In an effort to take advantage of the benefits of both the ping and tracert/traceroute commands, the pathping and mtr utilities were developed. Both of these tools take the functionality and information that can be obtained from these types of tools and provide a more detailed single picture of the path characteristics from a specific host to a specific destination. Figure 11 and 12 below show examples of these two tools and what information they provide.
Figure 11: Pathping
Figure 12: Mtr
1. Route
The last of the tools covered in this article is the route utility. This utility is used to display the current status of the routing table on a host. While the use of the route utility is limited in common situations where the host only has a single IP address with a single gateway, it is vital in other situations where multiple IP address and multiple gateways are available. Figure 13 below shows an example of the route utility being used on a Windows machine.
Figure 13: Route Utility