Transport Layer Security is a cryptographic protocol for encrypting and authenticating network communications, and replaces SSL. It is commonly used to secure Internet protocols such as HTTP.

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What are the exact protocol level differences between SSL and TLS?

This is a technical deep dive after this overview question was asked. What are the protocol differences between SSL and TLS? Is there really enough of a difference to warrant a name change? (versus ...
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5answers
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Functional implications of differences in SSL and TLS

I know that TLS is essentially a newer version of SSL, and that it generally supports transitioning a connection from unsecured to secured (commonly through a STARTTLS command). What I don't ...
22
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4answers
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How do I disable TLS 1.0 without breaking RDP?

Our credit card processor recently notified us that as of June 30, 2016 we will need to disable TLS 1.0 to remain PCI compliant. I tried to be proactive by disabling TLS 1.0 on our Windows Server 2008 ...
18
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1answer
18k views

How to inspect remote SMTP server's TLS certificate?

We have an Exchange 2007 server running on Windows Server 2008. Our client uses another vendor's mail server. Their security policies require us to use enforced TLS. This was working fine until ...
17
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4answers
31k views

Does HTTPS use TCP or UDP?

Does HTTPS use TCP or UDP?
13
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5answers
7k views

Do any well-known CAs issue Elliptic Curve certificates?

Background I've seen that Comodo has an elliptic curve root ("COMODO ECC Certification Authority"), but I don't see mention of EC certificates on their web site. Does Certicom have intellectual ...
12
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2answers
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How to enable TLS 1.1, 1.2 in IIS 7.5

We want to support web browsers utilizing TLS 1.1 and 1.2, which has been apparently implemented by Microsoft, but is turned off by default. So I went searching on Google and discovered some pages ...
12
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2answers
8k views

Configure OpenLDAP with TLS=required

Nowadays, OpenLDAP needs to be configured with ldapmodify cn=config, as describe here. But nowhere I can find how you configure it to only accept TLS traffic. I just confirmed that our server accepts ...
11
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3answers
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Fixing BEAST vulnerability on Apache 2.0 running on RHEL 4

I have a web server running Apache 2.0 on RHEL4. This server recently failed a PCI scan. Reason: SSLv3.0/TLSv1.0 Protocol Weak CBC Mode Vulnerability Solution: This attack was identified in 2004 and ...
10
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2answers
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Why is Internet Explorer 11 unable to connect to HTTPS sites when TLS 1.2 is enabled?

Normally I don't use Internet Explorer at all. I use it only in design time for interface tests (development machine and with unencrypted http). Every week I run the SSL Labs server test which says ...
9
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2answers
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How can I verify if TLS 1.2 is supported on a remote web server from the RHEL/CentOS shell?

I'm on CentOS 5.9. I'd like to determine from the linux shell if a remote web server specifically supports TLS 1.2 (as opposed to TLS 1.0). Is there an easy way to check for that? I'm not seeing a ...
9
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1answer
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How to disable SSLCompression on Apache httpd 2.2.15? (Defense against CRIME/BEAST)

I read about the CRIME attack against TLS Compression (CVE-2012-4929, CRIME is a successor to the BEAST attack against ssl & tls), and I want to protect my webservers against this attack by ...
9
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2answers
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How to disable TLS 1.1 & 1.2 in Apache?

I have an Ubuntu 12.04.2 LTS server running Apache 2.2.22 with mod_ssl and OpenSSL v1.0.1. In my vhosts config (everything else within which behaves as I would expect), I have the SSLProtocol line ...
8
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4answers
13k views

Is STARTTLS more safe than TLS/SSL?

In Thunderbird (and I assume in many other clients, too) I have the option to choose between "SSL/TLS" and "STARTTLS". As far as I understand it, "STARTTLS" means in simple words "encrypt if both ...
8
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1answer
4k views

Postfix TLS over SMTP - RCPT TO prompts renegotiation then 554 5.5.1 Error: no valid recipients

I've setup ispconfig3 on my debian six server, and here is a little smtp over ssl: The server is postfix AUTH PLAIN (LOL!) 235 2.7.0 Authentication successful MAIL FROM: lol@lol.com 250 2.1.0 Ok ...
8
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5answers
8k views

What is TLS and how does it compare to SSL?

Is TLS the "new" version of SSL? What features does it add, or security issues does it address? Can anything that supports SSL support TLS? What would be involved in making the switch? Is the ...
8
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2answers
482 views

How widely supported is forced TLS on inbound SMTP connections?

I run an MTA consisting of the standard Postfix, SpamAssassin, ClamAV, SPF/DKIM checks etc. This MTA is used for inbound email only, doesn't host any accounts and forwards any mail that passes said ...
7
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4answers
9k views

Failed tls handshake. Does not contain any IP SANs

I'm trying to set up logstash forwarder, but I have issues with making a proper secure channel. Trying to configure this with two ubuntu (server 14.04) machines running in virtualbox. They are 100% ...
7
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3answers
7k views

What's the difference between: Verisign Thawte Geotrust Rapidssl certs?

Verisign owns all these certificate issuing companies: Verisign Thawte Geotrust and Rapidssl. What is the difference between them and why is the price difference so great? Update: Here are just a ...
7
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4answers
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Disable SMTP AUTH on Port 25

Due to PCI-DSS, we are required to disable plaintext authentication. We've achieved this by encapsulating communications between our mail server and clients with TLS on port 465. The problem lies in ...
7
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1answer
3k views

Safest ciphers to use with the BEAST? (TLS 1.0 exploit) I've read that RC4 is immune

Now that the BEAST is public knowledge, TLS 1.0 is NOT safe to use (nor is SSL 3.0). I have seen reports that the RC4 cipher is unaffected (and is widely supported). Is that true? I know that TLS 1.1 ...
6
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2answers
1k views

Display a TLS icon for messages that are TLS secured (Outlook)

One of my colleagues at a large financial institution has customised Lotus Notes to show a TLS icon for messages that are TLS secured. I'm interested in imitating this feature in Outlook, and believe ...
6
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1answer
13k views

Disable SSL / TLS compression in Apache 2.2.x

Is there a way to disable SSL/TLS Compression in Apache 2.2.x when using mod_ssl? If not, what are people doing to mitigate the effects of CRIME/BEAST in older browsers? Related Links: ...
6
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3answers
9k views

Require TLS on RDP for all connections

I have a 2008 DC and a 2008 AD CS server and a Windows 7 client. What I would like is to require the certificate to be used when RDPing to the server. The certificate is valid, and if I connect ...
6
votes
1answer
153 views

Can I detect if the SSL client doesn't support Server Name Indication and provide the standard HTTP website in that case?

I will need to use SSL SNI, but unfortunately from a recent Cloudflare blogpost only 90% of the network supports it. How can I (for example, with nginx) detect if the client supports SNI and ...
6
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2answers
453 views

What effect does https traffic have on web cache proxy servers?

I just took two university courses on computer security and internet programming. I was thinking about this the other day: Web cache proxy servers cache popular content from servers on the web. This ...
6
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5answers
416 views

Is the world ready for name based HTTPS vhost service? [duplicate]

Possible Duplicate: Multiple SSL domains on the same IP address and same port? I'm developing a web app that MUST MUST MUST use HTTPS. It's kinda developed on the cheap though, and I really ...
6
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1answer
3k views

How can I let nginx log the used SSL/TLS protocol and ciphersuite?

My goal is to ensure proper security for clients connecting to my nginx. I'm following Mozilla's guide to configure TLS properly on my nginx installation, but I don't have an overview of the actual ...
6
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2answers
3k views

Why does IE think that my certificate is invalid?

I have my chained certificate from Dreamhost set up and working for all browsers. I have 2 sites with 2 certs from dreamhost, example.com and sub.example.com. All browsers are fine with the certs on ...
6
votes
2answers
2k views

Overhead of TLS/SSL on a TCP socket connection?

Is there any bandwidth overhead on using SSL on a TCP connection? I understand, of course, the processing/memory usage overhead in encrypting and decrypting packets, but as far as bandwidth is ...
6
votes
3answers
1k views

Monit failing to connect to Dovecot over SSL IMAP

I run Monit to keep check on processes on a Debian server. It's working as normal for all other services (Apache SSL, Postfix, SSH etc.) but Monit's checks on Dovecot are failing repeatedly. I think ...
6
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1answer
4k views

Third Party Wildcard Certificates for use with Microsoft NPS / RADIUS / PEAP

I want to replace the SSL certificate that is used for PEAP on our NPS server that is doing RADIUS authentication for our Cisco WLCs. The current certificate is a SSL certificate that does Client ...
6
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4answers
3k views

SSL connection errors from Apache

I'm running a (self-signed) SSL cert site on Apache/2.2.14 on Ubuntu 10.04, but various browsers are giving errors on half the connection attempts. Just now saw this transient error from Chrome: ...
5
votes
2answers
12k views

SSLCipherSuite - disable weak encryption, cbc cipher and md5 based algorithm

A developer recently ran a PCI Scan with TripWire against our LAMP server. They identified several issues and instructed the following to correct the issues: Problem: SSL Server Supports Weak ...
5
votes
2answers
675 views

How to fix the Logjam vulnerability in OpenVPN server config?

As of this writing (Day-2), there are quite few accurate guidelines as to how to mitigate Logjam for Apache and other web servers, such as this page: https://weakdh.org/sysadmin.html What are the ...
5
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2answers
265 views

Perfect Forward Secrecy (PFS) for mail servers

Perfect Forward Secrecy is an important enhancement to SSL/TLS communications, helping prevent captured SSL traffic from being decrypted even if the attacker has the private key. It's easy enough to ...
5
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2answers
1k views

detect weak encryption and outdated protocols

I'm looking for software that helps detecting applications that use weak encryption or outdated protocols in a central place. Sorry if that sounds vague. Maybe an example will help. Let's take a ...
5
votes
1answer
164 views

Is it possible to configure IIS to redirect based on the SSL cipher suite used for the connection?

With the announcement of POODLE, I would like my servers to accept SSL3.0 connections but have them serve a page which indicates that the user should update to a newer browser with TLS support. It ...
5
votes
2answers
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SSL/TLS Cipher Priority

I am working on trying to make sense of what is required for both PCI DSS compliance as well as FIPS compliance in relation to SSL/TLS cipher suites. I have been reading the guide here and here. ...
5
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3answers
2k views

What percentage of web users are running on browsers/OSes that support SNI? [closed]

Has anyone done any analysis (or know where I can find some!) on what proportion of internet users are using a browser/operating system combination that support SNI (Server Name Indication) SSL/TLS ...
5
votes
2answers
2k views

Exchange 2007 Cipher Suite Order

I'm experiencing issues receiving TLS encrypted e-mail from a specific domain. We entered into an agreement to use a 256-bit cipher and apparently our Exchange 2007 server on Windows Server 2003 ...
5
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2answers
3k views

Secure LDAP Authentication with Active Directory

We are working on a web project where we need to be able to bind to an active directory domain and then pass the user's credentials to the domain to make sure the user has successfully authenticated ...
5
votes
1answer
1k views

postfix TLS configuration for incoming gmx-mail

I set up my mailserver with postfix 2.7.1 and dovecot 1.2.15 and everything seemed to work just fine, but now I found out that people using @gmx.net addresses cannot send emails to me and rather ...
4
votes
4answers
12k views

CentOS openLDAP cert trust issues

# LDAPTLS_CACERTDIR=/etc/ssl/certs/ ldapwhoami -x -ZZ -H ldaps://ldap.domain.tld ldap_start_tls: Can't contact LDAP server (-1) additional info: TLS error -8172:Peer's certificate issuer has ...
4
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4answers
2k views

Server suddenly running out of entropy

Since a reboot yesterday, one of our virtual servers (Debian Lenny, virtualized with Xen) is constantly running out of entropy, leading to timeouts etc. when trying to connect over SSH / TLS-enabled ...
4
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1answer
4k views

How to switch between TLS 1.0 and SSL 3.0 at Java/JRE level?

I am using java 1.6. I have setup my tomcat as my ssl enabled server. And i have setup a ssl enabled client (java code). When i do a communication from my client to server. In java ssl dump in tomcat ...
4
votes
1answer
347 views

Completely getting rid of SSLv3 on Apache

Our security team is asking that we completely disable SSLv3 on some of our servers running Apache. I've used the SSLProtocol entry in the ssl.conf file (like SSLProtocol ALL -SSLv2 -SSLv3) and ...
4
votes
2answers
87 views

Is it necessary to purchase an OID for ADCS?

I am interested in utilizing ADCS to generate trusted certificates for internal web applications. However, from my readings it appears that I need to purchase an OID, which looks pretty expensive. Is ...
4
votes
1answer
460 views

Postfix SMTP client not verifying against system-wide CA certs with tls_append_default_CA

On my internet-facing Postfix SMTP server running Debian Wheezy, I'd like to set up a secure connection with some known servers. Some are my own, running my own PKI/CA, some are public SMTP servers ...
4
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2answers
2k views

Is it possible to enable TLS v 1.2 in Debian squeeze

I am currently running a Debian Squeeze server with Apache. My OpenSSL version is 0.9.8, and I would like to get up to a version capable of running TLS v 1.2. So far my research shows that this is ...