> Source: [sk182772](https://support.checkpoint.com/results/sk/sk182772)

# sk182772 - The browser does not reset the connection after receiving an RST packet

| Property | Value |
|----------|-------|
| Solution ID | sk182772 |
| Date Created | 2024-11-06 |
| Last Modified | 2024-11-12 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R82, R81.20, R81.10 (EOS) |

## Symptoms

- * The browser does not reset the connection after receiving a RST packet.  

  Example environment:  

  ```
  
    --------         ------------------         -----------------
   | Host_A |-------| Security Gateway |-------| Internet Server |
    --------         ------------------         -----------------
                               |
                               |
                     ---------------------
                    | Internal Web Server |
                     ---------------------
  ```

  The internal web server provides some web content, including JavaScript or CSS from the Internet. However, internal hosts are not permitted to access the Internet directly.  
  Access rule is:  

  ```
  
  Source:      Host-A
  Destination: Internet
  Services:    HTTPS
  Action:      Reject
  ```

  When the internal hosts navigate to the local web server, we expect to receive RST packets when the browser attempts to access the Internet JavaScript/CSS. This way, the browser can display the local web server content faster.

  <br />

* Wireshark capture on Host-A does not show the RST packet for connections to Internet servers.

* Running Kernel debug with the command: `"fw ctl zdebug + drop | grep <Host-A IP> | grep <Internet host server>"`, shows that the connection from Host-A to the Internet server IP address matches the above Reject rule. However, a subsequent connection from the Internet server IP address to Host-A that does not match any explicit rule and is dropped by the final cleanup rule.

* Running tcpdump/fw monitor/cppcap on the Security Gateway shows no return packets from the Internet server IP address to Host-A.

* When creating a new rule for the reverse connection:

  ```
  
  Source:      Internet
  Destination: Host-A
  Services:    HTTPS
  Action:      Accept
  ```

  Placed above the last cleanup rule for temporary verification purposes, a Wireshark capture on Host-A shows the RST packet after the first SYN packet.   
  However, Host-A sends retransmission packets to the Internet server IP, but the Internet server does not respond, causing the browser not to report the 'ERR_CONNECTION_RESET' error.

## Cause

The browser does not support resetting the connection on the first SYN packet.

## Solution

This solution requires authentication. Please log in to view the full solution.

---

# Agent Instructions

This content is from the Check Point Support Center (https://support.checkpoint.com), the official knowledge base for Check Point cybersecurity products.

## Navigating This Knowledge Base

- **Complete index**: [llms.txt](https://support.checkpoint.com/llms.txt)
- **All SK articles**: [SecureKnowledge Sitemap](https://support.checkpoint.com/sitemaps/secureknowledge-sitemap-index.xml)
- **SK article URL pattern**: `https://support.checkpoint.com/results/sk/{skId}`
- **Markdown responses**: AI bot User-Agents automatically receive `text/markdown` content