Posted by jpluimers on 2021/10/14
For my link archive; [Archive.is] .DS_Storoz on Twitter: “Alright, I’m rage-quitting the frontend, moving into infrastructure. (Seriously.) Where is my community for this? Who do I follow? What conferences do I go to? Please and thanks and RT!”
Keywords:
–jeroen
Posted in Amazon S3, Amazon SES, Amazon.com/.de/.fr/.uk/..., AWS Amazon Web Services, Cloud, Containers, Docker, Infrastructure, Kubernetes (k8n), Power User | Leave a Comment »
Posted by jpluimers on 2021/08/10
*n*x:
# nslookup -type=TXT amazonses.com | grep "v=spf1" amazonses.com text = "v=spf1 ip4:199.255.192.0/22 ip4:199.127.232.0/22 ip4:54.240.0.0/18 ip4:69.169.224.0/20 ip4:76.223.180.0/23 ip4:76.223.188.0/24 ip4:76.223.189.0/24 ip4:76.223.190.0/24 -all"IWindows
C:\>nslookup -type=TXT amazonses.com | find "v=spf1" Non-authoritative answer: "v=spf1 ip4:199.255.192.0/22 ip4:199.127.232.0/22 ip4:54.240.0.0/18 ip4:69.169.224.0/20 ip4:76.223.180.0/23 ip4:76.223.188.0/24 ip4:76.223.189.0/24 ip4:76.223.190.0/24 -all"
These addresses use a compact CIDR notation to denote ranges of networks containing ranges of network IPv4 addresses.
(this is linux sendmail only)
Converting the nslookup outout to a CIDR based sendmail /etc/mail/access excerpt goes via a pipe sequence of multiple sed commands:
# nslookup -type=TXT amazonses.com | grep "v=spf1" | sed 's/\(^.*"v=spf1 ip4:\| -all"$\)//g' | sed 's/\ ip4:/\n/g' | xargs -I {} sh -c "prips {} | sed 's/$/\tRELAY/g'" 199.255.192.0 RELAY 199.255.192.1 RELAY ... 76.223.190.254 RELAY 76.223.190.255 RELAY
What happens here is this:
spf1 records using grep..*v=spf1 ip4:) and tail ( -all") of the output, see [WayBack] use of alternation “|” in sed’s regex – Super User. ip4: with newlines (so the output get split over multiple lines), see [WayBack] linux – splitting single line into multiple line in numbering format using awk – Stack Overflow.xargs with the sh trick to split the CIDR list into separate arguments, and prips (which prints the IP addresses for a CIDR); see:
xargs with sh: [WayBack] shell – Piping commands after a piped xargs – Unix & Linux Stack Exchangeprips: [WayBack] prips / Prips · GitLab and [WayBack] Sendmail Open Source FAQs 0 (PDF).cidrexpand (which requires Perl), see [WayBack] sendmail access file and cidrexpand and [WayBack] cidrexpand in sendmail | source code search engine$) with a tab followed by RELAY, see
You can append the output of this command to /etc/mail/access, then re-generate /etc/mail/access.db and restart sendmail; see for instance [WayBack] sendmail access.db by example | LinuxWebLog.com.
Without the xargs, the output would look like this:
# nslookup -type=TXT amazonses.com | grep "v=spf1" | sed 's/\(^.*"v=spf1 ip4:\| -all"$\)//g' | sed 's/\ ip4:/\n/g' 199.255.192.0/22 199.127.232.0/22 54.240.0.0/18 69.169.224.0/20 76.223.180.0/23 76.223.188.0/24 76.223.189.0/24 76.223.190.0/24
–jeroen
Posted in *nix, *nix-tools, Amazon SES, Amazon.com/.de/.fr/.uk/..., Cloud, Communications Development, Development, Infrastructure, Internet protocol suite, Power User, sendmail, SMTP, Software Development | Leave a Comment »
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