Troubleshoot slow performance in Gmail

Advanced tests for administrators

As an administrator, you can use these advanced troubleshooting steps to diagnose your users' connections when they complain that Gmail is slow. 

Before you begin

You can ask your users to conduct a number of troubleshooting steps themselves by first determining these factors:

Run advanced tests

If you still can’t find the root problem, run the following advanced tests and analyses.

 Step 1. Run a ping test against Google mail servers

A ping test calculates the approximate time it takes for a small message to make a round trip to and from the server.

1. Run a ping test.

On Windows®:

  1. Open a command prompt.
  2. Click Start and then Run.
  3. Type cmd and press Enter.
  4. At the prompt, enter ping -n 10 mail.google.com and press Enter:

On Mac® OS X® and Linux®:

  1. Open a terminal. 
  2. At the prompt, enter ping -c 10 mail.google.com and press Enter.

2. Interpret the Google mail server ping test results.

  1. Check for packet loss. At the bottom of the ping result, you see "X% packet loss." In general, any amount of packet loss indicates a problem in the route between you and the Gmail server.

  2. Check for long round-trip times. At the bottom of the ping result, you see "round-trip min/avg...". In general, the average round-trip time should not be greater than .05 seconds (50 milliseconds). If the round-trip time is greater than 500 ms, it signifies network issues that need to be investigated. Proceed to the traceroute test.

Step 2. Run a traceroute test against Google mail servers

Run a traceroute test against Google mail servers if the ping test shows a round-trip time of greater than 50 ms or if there is any amount of packet loss. This test shows the route the packets take and helps identify the network routers experiencing delays.

1. Run a traceroute test.

On Windows:

  1. Open a command prompt.
  2. Click Start and then Run.
  3. Type cmd and press Enter.
  4. At the prompt, enter tracert mail.google.com and press Enter:

On  Mac OS X and Linux:

  1. Open a terminal. 
  2. At the prompt, enter traceroute mail.google.com and press Enter:

2. Interpret the Google mail server traceroute results.

Look for a circuitous route, lengthy hops, and connection drops.

  1. Check for long round-trip times. Examine each line and ensure none exceeds 3 seconds (3,000 ms). Here are example results of excessive latency:

    11  ppp-151-164-39-20.rcsntx.swbell.net (151.164.39.20) 9100.287 ms  8100.077 ms  9100.065 ms
     
  2. Run the traceroute command a few more times to make sure that the issue with the hop or host in question is persistent.
     
  3. Check for large numbers of hops.

    In general, barring a network routing issue, a path between a client and an end server should not exceed 20 or 25 hops.
     
  4. If you see traceroute output greater than 20 or 25 hops, please re-run the test to confirm the behavior.
     
  5. Check your local network environment for any issues that may cause excessive hops.
     
  6. Proceed to the DNS ping test.

Step 3. Run a ping test to your internal DNS server

Google determines users' locations by looking at where the associated DNS requests are coming from and then sends them to the closest Google servers for improved performance. If the users are using a nameserver in a different geographic location, Google is likely sending them to distant servers. By pinging your local DNS server, you can find out how far you are from it.

1. Run a ping test.

On Windows:
  1. Open a command prompt.
  2. Click Start and then Run..
  3. Type cmd and press Enter.
  4. At the prompt, enter ipconfig /all and press Enter.

  5. In the resulting connection information output, look for the DNS Servers section and identify the IP address of the DNS server being used.
  6. Conduct a ping test as you did against Google mail servers, replacing mail.google.com with the numeric IP address of your nameserver.

On Mac OS X and Linux:

  1. Open a terminal. 
  2. At the prompt, enter cat /etc/resolv.conf and press Enter.
  3. Note the first IP address that’s listed as a nameserver.
  4. Conduct a ping test as you did against Google mail servers, replacing mail.google.com with the numeric IP address of your nameserver.

2. Interpret your DNS server ping test results.

When you ping the local DNS server, the duration shouldn't be more than 10 to 30 ms. In most networks, the value is less than 2 ms. If your result is more than that, a Virtual Private Network (VPN), or other internal enterprise network may be routing the users' traffic to another city. In this case, accessing Gmail can be slow. We recommend you contact your network administrator to see how latency to DNS can be reduced. This may involve network-level changes or something as simple as configuring user machines to access different DNS servers.

Still need help?

Contact Google Cloud Support.
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