Hi
@zhaoshengyun
Gmail imposes a limit on the number of emails you can send within a given timeframe, such as per minute or hour. If you exceed this limit, which is determined by your reputation, Gmail uses its rate-limiting proxy servers to fetch all source links. These proxy servers, which have different IP addresses from Gmail's image proxy servers, can affect how email opens are tracked.
Instead of following
@twisted1919's advice to filter out bots from tracking during campaign creation, a more effective approach might be to add the IP ranges of Google's rate-limiting servers to the list of IPs excluded from open tracking. This setting can be found under backend>settings>campaigns>exclude-ips-from-tracking.
I have compiled a list of such IP ranges and made it available in a GitHub repository:
https://github.com/pksh71/gmail-bot-email-open-click-ip-ranges
Example IPs 74.125.149.96 has a hostname
96.149.125.74.in-addr.arpa domain name pointer rate-limited-proxy-74-125-149-96.google.com.
@twisted1919 , I've tested the method of excluding robots from tracking during campaign setup, but found it to be imprecise. In my tests, it failed to record legitimate opens, including my own tests using the Gmail app on Android.
It seems that the current method might rely on detecting user-agents, which can be problematic since Gmail uses a variety of user-agents for its proxies, and there are many others used by different providers. Perhaps we could consider adding a feature that allows the blocking of specific user-agents, similar to the existing option for IP addresses.
Regards
Pradeep