MobileRead Forums - View Single Post - KOReader Crashes When Enabling HTTP Inspector

cheekyp123 · 05-11-2025, 04:11 AM

Hi all,

I’m working on a remote page-turning setup for KOReader on my jailbroken Kindle and hoped to use the built-in HTTP Inspector for the job. The idea is to send HTTP requests (e.g. from a PC or button box) to turn pages remotely—simple, hands-free reading under the covers!
Like is detailed in this blog post:https://pageturnerkindle.wordpress.c...roken-kindles/

However, whenever I enable the HTTP Inspector plugin in KOReader, it immediately crashes. Looking at the logs, I see this:

Code:

FATAL: module ip_tables not found
Cannot initialize filter: table doesn’t exist
Do you need to insmod?

It seems like it tries to manipulate iptables, but the Kindle kernel lacks the ip_tables module entirely.

To debug further, I ran an nmap scan of the device:

Code:

Starting Nmap 7.96 ( https://nmap.org ) at 2025-05-10 14:50 GMT Summer Time
Nmap scan report for 192.168.1.225
Host is up (0.0054s latency).
Not shown: 65037 closed tcp ports (reset), 492 filtered tcp ports (no-response)
PORT      STATE SERVICE
22/tcp    open  ssh
23/tcp    open  telnet
12608/tcp open  unknown
20460/tcp open  unknown
20470/tcp open  unknown
MAC Address: AC:XX:XX:XX:XX:XX (Amazon Technologies)

This suggests a few random high ports are open—possibly left by other services—so the device isn’t blocking everything. But without iptables, I can’t seem to bind HTTP Inspector to a new port or even start it without a crash.

Has anyone successfully used HTTP Inspector, or any other lightweight HTTP listener, on a Kindle (without iptables)? Or better yet—does anyone know if KOReader can be made to respond to requests on one of these already-open ports, or how to actually open ports? Given i'm running USB network KUAL module that is presumably the reason port 22 is open. So this must be possible?

I’m also experimenting with writing a simple Lua plugin to handle next/prev commands, but that seems to crash koreader too, likely for the same reason.

Any ideas or prior experience appreciated!

Thanks in advance.

I have kindle basic 2 (8th gen)

05-11-2025, 04:11 AM	#1
cheekyp123 Junior Member Posts: 1 Karma: 10 Join Date: Jun 2022 Device: KT3W / Kindle basic 2 / kindle 8?	KOReader Crashes When Enabling HTTP Inspector – iptables Error on Jailbroken Kindle Hi all, I’m working on a remote page-turning setup for KOReader on my jailbroken Kindle and hoped to use the built-in HTTP Inspector for the job. The idea is to send HTTP requests (e.g. from a PC or button box) to turn pages remotely—simple, hands-free reading under the covers! Like is detailed in this blog post:https://pageturnerkindle.wordpress.c...roken-kindles/ However, whenever I enable the HTTP Inspector plugin in KOReader, it immediately crashes. Looking at the logs, I see this: Code: FATAL: module ip_tables not found Cannot initialize filter: table doesn’t exist Do you need to insmod? It seems like it tries to manipulate iptables, but the Kindle kernel lacks the ip_tables module entirely. To debug further, I ran an nmap scan of the device: Code: Starting Nmap 7.96 ( https://nmap.org ) at 2025-05-10 14:50 GMT Summer Time Nmap scan report for 192.168.1.225 Host is up (0.0054s latency). Not shown: 65037 closed tcp ports (reset), 492 filtered tcp ports (no-response) PORT STATE SERVICE 22/tcp open ssh 23/tcp open telnet 12608/tcp open unknown 20460/tcp open unknown 20470/tcp open unknown MAC Address: AC:XX:XX:XX:XX:XX (Amazon Technologies) This suggests a few random high ports are open—possibly left by other services—so the device isn’t blocking everything. But without iptables, I can’t seem to bind HTTP Inspector to a new port or even start it without a crash. Has anyone successfully used HTTP Inspector, or any other lightweight HTTP listener, on a Kindle (without iptables)? Or better yet—does anyone know if KOReader can be made to respond to requests on one of these already-open ports, or how to actually open ports? Given i'm running USB network KUAL module that is presumably the reason port 22 is open. So this must be possible? I’m also experimenting with writing a simple Lua plugin to handle next/prev commands, but that seems to crash koreader too, likely for the same reason. Any ideas or prior experience appreciated! Thanks in advance. I have kindle basic 2 (8th gen)