Linux Login

Just an aside comment. Tried to login in via SSH and miss-typed the login name. Tried to hit return for password to get back to login name and just was prompted for password again. Did that and tried ^X and then ^C and ended up blocked by intrusion protection.
Possibly null password should have cycled back to login name.

Added my network to the white list (192.168.1.0/32) but not sure if that should be necessary. My blocked IP vanished but sill cannot connect via SSH. Maybe after time out.

Yes, I’m in now.

Did you restart fail2ban?

192.168.1.0/32 is a network of one host and that host is definitely not the machine you are trying to de-protect :slight_smile: you probably mean 192.168.1.0/24 which will be all 256 addresses in your lan. Fopr how it all works, perhaps start with:-

http://www.penguintutor.com/linux/basic-network-reference

You can of course just stop fail2ban (service fail2ban stop) while you get yourself together, or perhaps just stop the ssh jail (fail2ban-client stop ssh) if that is all that is blocking you.

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Oh, thanks for that. 192.168.1.0/32 was what displayed in the band window so I tried that.

I have to add the I have never really understood what the number 24 represented and have never taken the time to look it up. Always more to learn.

I really wish people would stop creating “TCP/IP guides” that talk about “class a b c etc.” since modern IP networks are classless… Class only has to do with how routing protocols work and needs to be struck from these texts.

The / notation is CIDR notation. You can represent a single IP with the following notation:

192.168.1.1

or

192.168.1.1 mask 255.255.255.255

or

192.168.1.1/32

The / notation, called CIDR notation, was developed as shorthand for writing out subnets. For subnetting /24 networks here are the most common ones:

/32 - single IP
/30 - 2 IPs, 1 subnet number 1 broadcast number, 255.255.255.252
/29 - 6 IPs, 1 subnet 1 broadcast, mask 255.255.255.248
/28 - 14 IPs, 1 subnet, 1 broadcast, mask 255.255.255.240

Most people use charts I have several. Google “IP subnet chart image” There is no need to dig into the bit mathematics unless you are really into that sort of thing.

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Thanks, I get it. It is shorthand for the bits in the mask.

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