I have an active SSL cert for "domain.com" that is hosted on Server1. If I have a mail service that is hosted on Server2 and uses the same domain root, "#domain.com", would I be able to use the same cert? Or do I need to buy a second SSL for the same domain on the mail server?
Your certificate's SAN (Subject Alternative Name) should either contain both of the target domains or a wildcard domain like *.domain.com.
Additionally, the private key must be copied from server 1 to server 2.
If you follow the suggestions above, you should be good to go.
Related
I just installed a Cloudflare Origin CA ssl certificate on my server. Because I have many domains on this server, I configured the certificate to protect them all, so I can use only one certificate for all my domains (domain1.com, domain2.com, etc...).
I went to check my ssl was working properly with the service whynopadlock.com, and I realized this service can list ALL of my domain names on the server by just accessing domain1.com? Are all the domains in a certificate meant to be public, is this normal behavior and can I avoid it?
I also noticed whynopadlock.com lists some domains in the certificate that are not mine. Does it mean Cloudflare is using the same certificate for many different users?
Are all the domains in a certificate meant to be public, is this normal behavior and can I avoid it?
All certificate subject alternate names are part of the certificate and are sent to every client that tries to connect securely.
There is no way to avoid it unless you want to use separate certificates for each domain.
I also noticed whynopadlock.com lists some domains in the certificate that are not mine.
Cloudflare states that this is normal:
Are Cloudflare SSL certificates shared?
Universal SSL certificates are shared across multiple domains for
multiple customers. If certificate sharing is a concern, Cloudflare
recommends a Dedicated or Custom SSL certificate.
Note that Cloudflare (as of Feb 2019) does provide dedicated certificates if you do not want to use a shared certificate.
I am currently using CloudFlare and recently added an SSL certificate to my script.
Before hand, I added an A record (proxied with CloudFlare) that pointed to my TS IP. It worked like this: ts.domain.net:PORT
However, after I added the SSL cert, it doesn't seem to work anymore.
If it matters, my main site IP is also (of course) proxied under CloudFlare
Thanks!
Every certificate contains one or more Subject Alternative Names. You can use the certificate only on domains that are listed as SAN within the certificate, as long as you don't have a wildcard certificate that can be used on a all subdomain, eg. *.mydomain.net.
Therefore for your TS server you need a certificate that contains the SAN ts.domain.net. If your current certificate is only for domain.net you need another certificate for your Teamspeak subdomain.
I am going to use an SSL certificate on my chat application based on XMPP(ejabberd) which is hosted on an IP.
So, I will be using the IP as the common name when I am generating my SSL certificate. But the server that has everything hosted on it, refers to the IP using a hostname as abcd.yourserver.net.
Therefore, I am confused as to if I have to use the IP or this weird hostname while generating my SSL certificate and if in future I decide to use a domain name instead of the IP for my application, will I have to buy a new SSl certificate or can I regenerate the old one. Also, can I change the type like wilcard or single certificate?
P.S. I have never bought an SSL certificate, so forgive me if the question is newbish.
When generating an SSL certificate for an XMPP server, you have to use the domain name of your XMPP service.
I am quite confused here:
I use DNSMadeeasy to manage my DNS. I have two apps.
One is Heroku hosted, and has https on https://example.com - Heroku has many great tutorials to setup the certificate, it hasn't been a problem.
The other one is a wordpress, hosted in 1and1 (though it shouldn't matter here), and is reachable at http://subdomain.example.com and we want it to be available at https://subdomain.example.com
1and1 does sell SSL certificate, but their automated setup works only when one uses their services for DNS also, as they say. Their support says it should be DNSMadeEasy which should be hosting our SSL certificate. I have the feeling it is not true, because for https://example.com, DNSMadeEasy was never involved.
Questions:
When does certificate querying occurs? Before, After, or in parallel of DNS resolution?
Who is hosting a certificate? The DNS provider? The server (accessible like a sitemap.xml at the root for instance)? A third party?
To enlarge the case, in general if I have a personal server with a fix IP, how can I communicate through https with a valid certificate?
In my case, how can I get my way out of it to make https://subdomain.example.com work?
You are right for not believing the 1and1 suggestion.
To answer your questions:
When does certificate querying occurs? Before, After, or in parallel
of DNS resolution?
A client resolves domain name to an IP address first. So DNS resolution happens first.
Who is hosting a certificate?
The server (in simplistic terms) hosts the certificate.
When a client wants to connect to your site (via HTTPS) it will first establish a secure connection with that IP address on port 443 (this is why usually (without SNI) you can only have one SSL certificate per IP address). As part of this process (which is called handshake) a client can also specify a server name (so-called server name extension) - this is a domain name of your site. This is useful if you have an SSL certificate that is valid for multiple domains.
A good/detailed explanation how it works can be found here
http://www.moserware.com/2009/06/first-few-milliseconds-of-https.html
if I have a personal server with a fix IP, how can I communicate
through https with a valid certificate?
Your server will need to be able to respond on port 443 and have/host an SSL certificate for a domain that resolves to that IP address.
In my case, how can I get my way out of it to make
https://subdomain.example.com work?
You need to purchase a certificate for subdomain.example.com and install it on the wordpress server.
Usually in hosted solution like yours you have 2 options:
Buy the SSL certificate via the provider (1and1 in your case) - a simpler option, they will configure everything for you.
Buy the SSL certificate yourself. Here you will most likely need to login to your 1and1/Wordpress management interface and generate a CSR (essentially a certificate request). Then you purchase the SSL certificate using this CSR and then you can install it via the same management interface.
The process will look similar to this:
http://wpengine.com/support/add-ssl-site/
I have a site that has subdomains for each user and a wildcard SSL Cert
https://user1.mysite.com
https://user2.mysite.com
The question is can someone set a cname record such as user1.theirsite.com -> user1.mysite.com and have it still use https?
Will it work if they install a SSL Cert on their server to secure the connection?
Thanks
The best way for this to work is if they arrange with you to have your SSL certificate include their "alias" as a Subject Alternate Name extension in your X.509 certificate.
This is the approach used by some CDNs when they host https sites for clients - they put all of the known site names that are hosted on one server in one large SSL certificate, and then the clients use CNAMEs to point their domain at the right CDN server.
The host name and certificate verification (and in fact, checking that SSL is used at all) are solely the responsibility of the client.
The host name verification will be done by the client, as specified in RFC 2818, based on the host name they request in their URL. Whether the host name DNS resolution is based on a CNAME entry or anything else is irrelevant.
If users are typing https://user1.theirsite.com/ in their browser, the certificate on the target site should be valid for user1.theirsite.com.
If they have their own server for user1.theirsite.com, different to user1.mysite.com, a DNS CNAME entry wouldn't make sense. Assuming the two hosts are effectively distinct, they could have their own valid certificate for user1.theirsite.com and make a redirection to https://user1.theirsite.com/. The redirection would also be visible in the address bar.
If you really wanted to have a CNAME from user1.theirsite.com to user1.mysite.com, they might be able to give you their certificate and private key so that you host it on your site too, using Server Name Indication (assuming same port, and of course same IP address since you're using a CNAME). This would work for clients that support SNI. There would however be a certain risk to them in giving you their private keys (which isn't generally recommended).
The following is set up and working:
DNS entry for a.corp.com -> CNAME b.corp2.com -> A 1.2.3.4
The haproxy at 1.2.3.4 will serve up the cert for a.corp.com and the site loads fine from a webserver backend.
So, on your server you will need user1.theirsite.com cert and it will work.