Onnowpurbo at 13:08, 25 January 2026

2026-01-25T13:08:41Z

Onnowpurbo: Created page with " ssh -oHostKeyAlgorithms=+ssh-rsa root@192.168.0.4"

2024-01-07T22:48:38Z

Created page with " ssh -oHostKeyAlgorithms=+ssh-rsa root@192.168.0.4"

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ssh -oHostKeyAlgorithms=+ssh-rsa root@192.168.0.4

← Older revision		Revision as of 13:08, 25 January 2026
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	ssh -oHostKeyAlgorithms=+ssh-rsa root@192.168.0.4		ssh -oHostKeyAlgorithms=+ssh-rsa root@192.168.0.4
		+
		+
		+	Ini error klasik SSH modern vs OpenWRT lama 👍
		+	Bukan salah jaringan—algoritma kriptografinya tidak cocok.
		+
		+	---
		+
		+	## 🔍 Akar Masalah
		+
		+	Pesan error:
		+
		+	```
		+	Unable to negotiate with 192.168.1.1 port 22:
		+	no matching host key type found.
		+	Their offer: ssh-rsa
		+	```
		+
		+	Artinya:
		+
		+	* OpenWRT hanya menawarkan host key lama: `ssh-rsa`
		+	* OpenSSH modern (Ubuntu 22.04 / 24.04) menolak `ssh-rsa` karena:
		+
		+	* SHA-1 dianggap tidak aman
		+	* Dinonaktifkan by default sejak OpenSSH 8.8+
		+
		+	👉 Jadi SSH client menolak handshake, bukan server down.
		+
		+	---
		+
		+	## ✅ Solusi 1 (Paling Cepat & Aman Secara Praktis)
		+
		+	Aktifkan `ssh-rsa` hanya untuk host itu saja
		+
		+	```bash
		+	ssh -o HostKeyAlgorithms=+ssh-rsa \
		+	-o PubkeyAcceptedAlgorithms=+ssh-rsa \
		+	root@192.168.1.1
		+	```
		+
		+	✔ Cocok untuk:
		+
		+	* Lab
		+	* OpenWRT lama
		+	* Akses darurat
		+
		+	---
		+
		+	## ✅ Solusi 2 (Lebih Rapi, Disarankan untuk Lab)
		+
		+	Tambahkan konfigurasi khusus di `~/.ssh/config`
		+
		+	```bash
		+	nano ~/.ssh/config
		+	```
		+
		+	Isi:
		+
		+	```ini
		+	Host openwrt
		+	HostName 192.168.1.1
		+	User root
		+	HostKeyAlgorithms +ssh-rsa
		+	PubkeyAcceptedAlgorithms +ssh-rsa
		+	```
		+
		+	Lalu login cukup:
		+
		+	```bash
		+	ssh openwrt
		+	```
		+
		+	✔ Aman karena hanya berlaku untuk OpenWRT itu
		+	✔ Tidak menurunkan keamanan global
		+
		+	---
		+
		+	## ⚠️ Solusi 3 (Tidak Disarankan – Global)
		+
		+	Edit `/etc/ssh/ssh_config`
		+
		+	```bash
		+	sudo nano /etc/ssh/ssh_config
		+	```
		+
		+	Tambahkan:
		+
		+	```ini
		+	Host *
		+	HostKeyAlgorithms +ssh-rsa
		+	PubkeyAcceptedAlgorithms +ssh-rsa
		+	```
		+
		+	❌ Tidak disarankan
		+
		+	* Melemahkan keamanan semua SSH
		+	* Melanggar best practice security
		+
		+	---
		+
		+	## ⭐ Solusi TERBAIK (Jika Bisa Update OpenWRT)
		+
		+	Jika OpenWRT versi cukup baru (≥ 22.x):
		+
		+	### 1️⃣ Install host key modern
		+
		+	```bash
		+	opkg update
		+	opkg install openssh-keygen
		+	```
		+
		+	### 2️⃣ Generate key baru
		+
		+	```bash
		+	ssh-keygen -A
		+	```
		+
		+	Pastikan ada:
		+
		+	* `ssh-ed25519`
		+	* `ecdsa-sha2-nistp256`
		+
		+	### 3️⃣ Restart SSH
		+
		+	```bash
		+	/etc/init.d/sshd restart
		+	```
		+
		+	✔ Setelah itu SSH tanpa opsi tambahan
		+	✔ Paling aman & future-proof
		+
		+	---
		+
		+	## 🧠 Ringkasan Cepat
		+
		+	\| Kondisi \| Solusi \|
		+	\| -------------- \| --------------------------------------- \|
		+	\| Butuh cepat \| `ssh -o HostKeyAlgorithms=+ssh-rsa ...` \|
		+	\| Lab / edukasi \| `~/.ssh/config` (disarankan) \|
		+	\| Produksi \| Upgrade OpenWRT + regenerate key \|
		+	\| Jangan lakukan \| Enable ssh-rsa global \|
		+
		+	---
		+
		+	## 📌 Catatan Penting (Konteks Sistem Operasi)
		+
		+	> Ini contoh nyata evolusi OS security
		+	> Kernel & userland boleh sama-sama Linux, tapi:
		+	>
		+	> * crypto policy berubah
		+	> * default security makin ketat
		+	> * OS lama tetap jalan → tapi harus di-bridge
		+
		+	Ini materi emas untuk:
		+
		+	* Kernel vs userland
		+	* Backward compatibility
		+	* Security hardening
		+
		+	Kalau mau, saya bisa:
		+
		+	* Jadikan ini studi kasus di modul OpenWRT / Networking Stack
		+	* Buat praktikum troubleshooting SSH modern
		+	* Tambahkan diagram handshake SSH lama vs baru
		+
		+	Tinggal bilang 😉

OpenWRT: ssh versi lama - Revision history

Onnowpurbo at 13:08, 25 January 2026

Onnowpurbo: Created page with " ssh -oHostKeyAlgorithms=+ssh-rsa root@192.168.0.4"