I need to be able to SSH into a device on my network. Normally I am able to simply ssh into its local IP address. I recently ran an nmap scan on it, and now when I try to ssh into its local IP address, I recieve the following:
kex_exchange_identification: read: Connection reset by peer
Connection reset by <IP> port 22
This network is setup in a somewhat unique way. It has one router that manages the Wi-Fi network (what my machine is connected to) which is connected to another box that also acts as the modem. IP addresses that are connected to the Wi-Fi box start with 192.168, whereas those connected to the modem box start with 10.0. The device I am trying to access is connected to the modem box.
Historically, just typing in its 10.0. local address has allowed me to ssh into it with no issue, even though my device is on the 192.168 network, and arp -a does not show it.
Checking the ssh logs of the device via journalctl -fu ssh, I can see that every failed ssh attempt is accompanied by the following message:
Connection reset by 10.0.0.96 port 49949 [preauth]
I do not recognize the IP above, and the port changes every time.
Is this some sort of anti-spam protection that was triggered by my use of nmap? I know it's not just my computer because I am unable to ssh into the device from anything else on my network.
Note that connecting to a VPN then using SSH to connect to the external IP address (which is port-forwarded properly) works, as does connecting via ssh to the machine from the machine itself (127.0.0.1)l
How can I fix this issue?
Very late answer here. It turns out, I was on some sort of temporary block because nmap tripped some limit. Just waiting a while caused the block to expire.