Determine Causes of IMAP Bandwidth Usage

Question

How do you determine causes of IMAP bandwidth usage?

Answer

If a cPanel account has large amounts of IMAP Bandwidth, it is often difficult to determine the exact email account or client causing the usage.

Determine the usage of email addresses of a cPanel account:

# uapi --user=USERNAME Email list_pops | grep -oP "(?<=email:\s).*@.*" | while read address ;do printf "$address: ";grep "$address" /var/log/maillog*|awk -F'/' '/bytes/{SUM += $NF}END {print SUM/1024/1024/1024"gb"}';done | sort -rhk 2

Note: You need to replace USERNAME with the cPanel account's username.

Determine IPs that recently logged into an email account and the number of connections:

# grep "user@domain.tld" /var/log/maillog | grep -o '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}' | sort | uniq -c | sort -nr

Note: You need to replace user@domain.tld with the email account.

The Microsoft Outlook client can use large amounts of bandwidth if the Mail to keep offline value is set too high. You can view details on this here:

Work offline in Outlook - Microsoft Support