Issue with Large HTTP Chunked Uploads (Max Chunk Size 65536) – Apache HTTP Server 2.4.37

[Karthick B <karthick_25@xxxxxxxx>]

Hello Team,

I am currently using Apache HTTP Server 2.4.37 on Red Hat Enterprise Linux 8.9 (Ootpa) and I am facing an issue when attempting to upload large files via HTTP chunked transfer encoding.

Issue:

I am writing a TR143 HTTP client for upload testing using the HTTP chunked encoding method. The maximum chunk size I can send is 65536 bytes (64KB). If the chunked body exceeds this size, the Apache server closes the connection and throws the following error:

[Fri Feb 07 15:55:16.181694 2025] [proxy:debug] [pid 33209:tid 139866474014464] proxy_util.c(2368): AH00943: FCGI: has released connection for (*)
[Fri Feb 07 15:55:16.382861 2025] [http:info] [pid 33209:tid 139866474014464] (22)Invalid argument: [client 192.168.124.159:60326] AH01590: Error reading/parsing chunk
192.168.124.159 - - [07/Feb/2025:15:55:16 +0530] "PUT http://X.X.X.X/handler.php HTTP/1.1" 204 - "-" "tr143"

I want to send 4MB of data as an HTTP chunked body to achieve higher upload throughput. I have already tried the following steps:

Attempts to Resolve:

1. Increased the TCP buffer size on the Apache-hosted machine.
2. Adjusted the KeepAliveTimeout and LimitRequestBody in the httpd.conf.
3. Ensured that Timeout and ProxyTimeout were sufficiently large.
4. Verified that the operating system’s TCP buffer limits were adequate.
5. Checked that LimitRequestBody was set to handle the larger body size (4194304 bytes for 4MB).

However, none of these changes resolved the issue. Apache continues to close the connection and throws the error after a chunk size of 65536 bytes.

Request for Guidance:

Can anyone guide me on how to allow Apache to handle chunked upload data larger than 65536 bytes? Is there an internal limit within Apache that I need to configure to handle larger chunk sizes, or is there an additional setting I may have missed?

Configuration:

• Apache Version: 2.4.37
• Operating System: Red Hat Enterprise Linux 8.9 (Ootpa)
• Chunk Size Limitation: I need to send up to 4MB in chunked chunks.

I would appreciate any guidance or suggestions to resolve this issue.

Thank you!

Karthick