# Check SSL/TLS Certificates

### Check the expiration date of an SSL or TLS certificate

Open the Terminal application and then run the following command:

{% code overflow="wrap" %}

```
$ openssl s_client -servername {SERVER_NAME} -connect {SERVER_NAME}:{PORT} | openssl x509 -noout -dates
```

{% endcode %}

{% code overflow="wrap" %}

```
$ echo -n Q | openssl s_client -servername {SERVER_NAME} -connect {SERVER_NAME}:{PORT} | openssl x509 -noout -dates
```

{% endcode %}

### Finding SSL certificate expiration date from a PEM-encoded certificate file

The syntax is as follows query the certificate file for when the TLS/SSL certification will expire

{% code overflow="wrap" %}

```
$ openssl x509 -enddate -noout -in {/path/to/my/my.pem}

$ openssl x509 -enddate -noout -in /etc/nginx/ssl/www.cyberciti.biz.fullchain.cer.ecc

$ openssl x509 -enddate -noout -in /etc/nginx/ssl/www.nixcraft.com.fullchain.cer
```

{% endcode %}

### We can also check if the certificate expires within the given timeframe. For example, find out if the TLS/SSL certificate expires within next 7 days (604800 seconds):

```
$ openssl x509 -enddate -noout -in my.pem -checkend 604800

# Check if the TLS/SSL cert will expire in next 4 months #

$ openssl x509 -enddate -noout -in my.pem -checkend 10520000
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://wiki.smhuda.com/pentesting/infrastructure-security/network-infrastructure/check-ssl-tls-certificates.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.