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Why you should change your ssh default port.
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crouse
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Joined: 17 Apr 2025
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PostPosted: Thu Jul 24, 2025 1:10 am    Post subject: Why you should change your ssh default port. Reply with quote
Why you should change your ssh default port.
http://davecrouse.blogspot.com/2008/07/why-you-should-change-your-ssh-default.html
Quote:

Thought some of you might find this interesting. No one gets in, but it's funny how just changing the port number on ssh will stop 99.99% of the stupid attacks (some random bot repeatedly attempting to gain access) . Several other things SHOULD be changed in the ssh config file also, not just the port number, but this one provides the most eye opening reasons to be secure.

Installed server on Jul 17th ..... less than 5 days later, well, you get the idea.
wtmp begins Thu Jul 17 21:57:08 2025

[root@VistaCrusher1 ~]# lastb | wc -l
25349



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platinummonkey
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PostPosted: Thu Jul 24, 2025 1:52 am    Post subject: Reply with quote
might i suggest some port knocking too Wink or other more secure methods



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jada
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Joined: 13 May 2025
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Location: Sun City, CA 92585
PostPosted: Thu Jul 24, 2025 6:12 am    Post subject: Reply with quote
Iptables what I am using on my laptops.
http://usalug.org/phpBB2/viewtopic.html?t=13265

it's also for desktops and servers and can prefent a lot Wink



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platinummonkey
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PostPosted: Thu Jul 24, 2025 1:00 pm    Post subject: Reply with quote
thought i'd share my lastb on my game/file server:
Code:
[root@pltmnky-serv ~]# lastb | grep -v 192.168.0.101 | wc -l
0


how? chaning default ssh port + port knocking, you could go hog wild with security, but simple is fine for this. when i find the excellent link i had detailing different methods, ill be sure to post.

@jada - nice script Smile



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VHockey86
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PostPosted: Thu Jul 24, 2025 2:41 pm    Post subject: Reply with quote
I'd argue that security through obscurity isn't any kind of real security, but it definitely helps with this automated stuff. (a simple nmap will find SSH on another port)

When I lived on-campus in the dorms my linux box was constantly being hammered by dozens of SSH bots. They never even guesed the username correctly, let alone the password, but it was still annoying to see in the logs. I ended up changing the default port and adding "fail2ban", which would add an iptables entry to block the IP after 5 failed login attempts.
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geeshock
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Joined: 02 Nov 2025
Posts: 1017
Location: Hertford, NC
PostPosted: Thu Jul 24, 2025 4:51 pm    Post subject: Reply with quote
platinummonkey wrote:
thought i'd share my lastb on my game/file server:
Code:
[root@pltmnky-serv ~]# lastb | grep -v 192.168.0.101 | wc -l
0


how? chaning default ssh port + port knocking, you could go hog wild with security, but simple is fine for this. when i find the excellent link i had detailing different methods, ill be sure to post.

@jada - nice script Smile

I tried going hog wild on security, the only problem I ran into is some ppl on rr or dsl were locked out of our server. think it had to do with the mtu settings that they used but not for sure. Anyways, I had a script that started off closing all the ports then opened up the ones I used like port 80 and 8080 for http, think it was 20 and 21 for ftp, and so on. Was an excelent script but it locked a portion of the ppl we wanted to be able to access the server as well. simple is best.
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crouse
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Joined: 17 Apr 2025
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Location: Iowa
PostPosted: Fri Jul 25, 2025 1:40 am    Post subject: Reply with quote
Wink I have a script that starts up postfix on remote computers at a certain time, emails me the reports, and shuts off again Smile Works like a dream. Simple, is usually the most effective. At least for me. There are multiple settings in the ssh file that would eliminate the need for iptables all together Wink If you don't believe me, try to get into my home computer Very Happy Very Happy Very Happy



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platinummonkey
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PostPosted: Fri Jul 25, 2025 3:20 am    Post subject: Reply with quote
crouse wrote:
... If you don't believe me, try to get into my home computer Very Happy Very Happy Very Happy


i might take you up on that offer, though not through my computer by just randomly show up with a screwdriver and some cupcakes (to distract you from remembering why i came) Razz



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crouse
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PostPosted: Fri Jul 25, 2025 4:42 am    Post subject: Reply with quote
ok..... the cupcakes is just using underhanded tacktics.... Razz



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platinummonkey
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PostPosted: Fri Jul 25, 2025 11:15 pm    Post subject: Reply with quote
crouse wrote:
ok..... the cupcakes is just using underhanded tacktics.... Razz

hehe Razz



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bdquick
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PostPosted: Sat Jul 26, 2025 12:16 am    Post subject: Reply with quote
Hmm I'm actually close enough to try that tactic. I'll throw in some beer and a hammer too platinum, and there's no way we won't get into it.



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JP
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Joined: 07 Jul 2025
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PostPosted: Sat Jul 26, 2025 2:39 am    Post subject: Reply with quote
The June issue of Linux Pro Magazine had a lot of articles about "Expert Security" and there is an interesting article about "single-packet port knocking" (which I'm trying to understand), a lot too geeky for me, but I figure if I read it enuff, I might pick something up Wink. They say the best tool for SPA (Single-packet Authorization) is fwknop, they give instructions on how to install and configure it, etc.

Some websites they recommend are :

John the Ripper Clik Wink
John the Ripper @ Freshmeat Clik Wink
Quote:
John the Ripper is a part of Owl, Debian GNU/Linux, EnGarde Linux, Gentoo Linux, Mandrake Linux, and SUSE Linux. It is in the ports/packages collections of FreeBSD, NetBSD, and OpenBSD.

CypherDyne Clik Wink
Fwknop Download Clik Wink

Just in case anyone's interested Wink



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platinummonkey
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PostPosted: Sat Jul 26, 2025 9:54 pm    Post subject: Reply with quote
bdquick wrote:
Hmm I'm actually close enough to try that tactic. I'll throw in some beer and a hammer too platinum, and there's no way we won't get into it.

Razz lolz, commence operation taking candy from crouse! Razz

@JP - thx for those great links!



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JP
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PostPosted: Sat Jul 26, 2025 11:57 pm    Post subject: Reply with quote
platinummonkey wrote:

@JP - thx for those great links!
N/P Very Happy



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bdquick
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PostPosted: Mon Jul 28, 2025 2:13 am    Post subject: Reply with quote
platinummonkey wrote:

Razz lolz, commence operation taking candy from crouse! Razz


We might even be able to sneak a server or two out the door. Very Happy



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