27 Mar

Letsencrypt – Free signed automated SSL

Last year a really good project Letsencrypt came up. They key objective of this project is to help in securing web by pushing SSL everywhere.


Two key cool features

  1. It offer free signed SSL certs!
  2. It helps in setting up SSL via an agent seamlessly without having to deal with CSR, getting it signed & updating web server configuration.


At this stage Letsencrypt is itself a Certificate Authority and but it’s root certs are yet not in the browser. It’s probably going to take a while till all major browsers get their certificate.

To help on that one of it’s sponsors IdenTrust has signed their intermediate certs. Hence certs signed by Letsencrypt are accepted by all browsers right away. All certs signed by Letsencypt are signed by Letencrypt Authority X1 which have signature from DST Root CA X3 which is accepted by pretty much all popular browsers. You can read more about How it works here.


Here’s an example of SSL setup for say “demo.anuragbhatia.com” test domain which is already up and working without SSL. http://demo.anuragbhatia.com shows a plain text page. This is Apache running on Ubuntu server.

The Apache web config is pretty straightforward.



Step 1 – Grab the Letscrypt agent

git clone https://github.com/letsencrypt/letsencrypt


Step 2 – Execute the auto script

./letsencrypt-auto –help


This will grab all needed dependencies and will get the agent working.


Step 3 – Execute Letsencrypt auto script with it’s Apache plugin

./letsencrypt-auto –apache -d demo.anuragbhatia.com


It takes with a quick wizard and in the end I get:

Congratulations! You have successfully enabled

You should test your configuration at:


And it’s done!

Wizard got me a signed SSL and installed it in the apache config as well.

Screen Shot 2016-03-27 at 7.22.21 PM


Screen Shot 2016-03-27 at 7.22.37 PM


The agent created an addional Apache config with name demo.anuragbhatia.com-le-ssl.conf with following content


Here options-ssl-apache.conf plays an important role by using better security options. It’s config:


Some of the limitations 

  1. Signed SSL certs are valid only for 90 days and have to be renewed.
  2. Wildcard SSL certs are not supported yet.
  3. IPv6 is not supported in the autoconfig setup via client. One can always get certificate manually and use with IPv6 but agent is yet to support IPv6 (which I guess is from next month).


You can read more on their excellent documentation here and can also consider checking Presentation by Ashley Jones from PCH at SANOG on All TLS, all the time.


Have fun!

02 Dec

Messed up SPF record of mtsindia.in domain

Yesterday I called MTS Data Card support but their IVRS system was failing in giving me my balance details. Eventually I decided to email their support and glad to say support email was also easily available on their website.


Today I saw acknowledgement mail in spam. No big deal but I usually dig around genuine mails which go in spam to find exact cause. In this case I found mail was sent to me from  customercare.del@mtsindia.in and the server which relayed this mail was:

From email headers only one can tell main failure in mail:Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning customercare.del@mtsindia.in does not designate as permitted sender) smtp.mail=customercare.del@mtsindia.in  Thus clearly SPF failure. How?


Quick check on TXT record on root domain:

“v=spf1 a mx include:elabs5.com ~all” “v=spf1 ip4: ip4: ip4: ip4: ip4: ip4: ~all”


Here’s what’s wrong:

  1. Two v=spf1 in SPF isn’t really good. Very likely most of systems will hit for TXT record and will get any on random and eventually use it ignoring whitelisted IP’s in other completely.
  2. MTS missed to include the server which is placed on Tata Communications backbone in SPF record. Most of other IP’s mentioned in their SPF belong to Softlayer datacenter.
Hope someone from MTS will find this post and eventually work on fix! 🙂