Dovecot not responding
A user reported that she wasn't receiving any email. When I logged into
the mail servers, which runs
Dovecot for POP3/POP3S and used
Telnet to connect to
port 110, the
well-known port for POP3, I didn't get any response after I entered the
user command, so I exited to the telnet prompt with
$ telnet 127.0.0.1 110
Connected to 127.0.0.1.
Escape character is '^]'.
I logged into the root account and checked today's and yesterday's
maillog files for any references to Dovecot or POP3 issues, but saw none.
# grep -i dovecot /var/log/maillog
# grep -i dovecot /var/log/maillog.1
# grep -i pop3 /var/log/maillog.1
# grep -i pop3 /var/log/maillog
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Viewing the list of IP address ranges for AmazonAWS
If you need to create firewall rules for outgoing connectivity to
Web Services (AWS)
addresses, you can obtain a complete listing of the
AWS IP Ranges Are Now Available in JSON Format
- the download URL for the file
I downloaded the IP address range file from
is present on Apple
OS X/macOS systems and is available for Linux and many other operating
systems, including Microsoft Windows - see
Releases and Downloads.
$ curl -o ip-ranges.json https://ip-ranges.amazonaws.com/ip-ranges.json
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 99k 100 99k 0 0 191k 0 --:--:-- --:--:-- --:--:-- 191k
The following Python script can be used to extract just the
Classless Inter-Domain Routing (CIDR) address blocks, i.e.,
ip_prefix information from the JSON data stored in
the ip-ranges.json file downloaded from the
Amazon website and display it.
data = json.load(open('ip-ranges.json'))
for d in data["prefixes"]:
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