Ssh

Your ~/.ssh/config file is the most underused productivity tool in your terminal. Here’s how to make SSH work for you. Basic Structure H o s t H U P m o s o y s e r s t r t e N r a a 2 v m d 2 e e m r i 1 n 9 2 . 1 6 8 . 1 . 1 0 0 Now ssh myserver replaces ssh admin@192.168.1.100. ...

SSH is the front door to your servers. A weak SSH config is an open invitation to attackers. Here’s how to lock it down properly without locking yourself out. The Bare Minimum 1 2 3 4 5 6 7 8 9 10 11 12 13 # /etc/ssh/sshd_config # Disable root login PermitRootLogin no # Disable password authentication PasswordAuthentication no # Enable key-based auth only PubkeyAuthentication yes # Disable empty passwords PermitEmptyPasswords no 1 2 # Apply changes sudo systemctl restart sshd These four settings stop 99% of automated attacks. ...

Still typing ssh -i ~/.ssh/my-key.pem -p 2222 user@server.example.com? There’s a better way. The SSH Config File ~/.ssh/config transforms verbose commands into simple ones. # s # s s s B h A h e f f - t p o i e r r r o e ~ d / . s s h / p r o d - k e y . p e m - p 2 2 2 2 d e p l o y @ p r o d . e x a m p l e . c o m Basic Config # H H H o o o ~ s s s / t t t . H U P I H U I H U s p o s o d s o s d d o s s r s e r e t s e e e s e h o t r t n a t r n v t r / d N t g N t N c a d 2 i i a d i a d o m e 2 t n m e t m e n e p 2 y g e p y e v f l 2 F l F e i p o i s o i 1 l g r y l t y l 9 o o e a e 2 p d g . e . ~ i ~ 1 r e / n / 6 x . g . 8 a s . s . m s e s 1 p h x h . l / a / 1 e p m s 0 . r p t 0 c o l a o d e g m - . i k c n e o g y m - . k p e e y m . p e m Now just: ...

You’re still running a bastion host, aren’t you? That t3.micro sitting in a public subnet, port 22 open to… well, hopefully not 0.0.0.0/0, but let’s be honest — it’s probably close. Stop it. AWS Systems Manager Session Manager exists, and it’s better in every way. The Bastion Problem Bastion hosts have been the standard for decades. Jump box in a public subnet, SSH through it to reach private instances. Simple enough. ...

Every time you type ssh -i ~/.ssh/mykey.pem -p 2222 admin@192.168.1.50, you’re wasting keystrokes. The SSH config file exists to eliminate this friction. Basic Host Aliases Create or edit ~/.ssh/config: H H o o s s t t H U I H U I p o s d s o s d r s e e t s e e o t r n a t r n d N t g N t a d i i a d i m e t n m e t e p y g e p y l F l F 2 o i 2 o i 0 y l 0 y l 3 e 3 e . . 0 ~ 0 ~ . / . / 1 . 1 . 1 s 1 s 3 s 3 s . h . h 5 / 5 / 0 p 1 s r t o a d g _ i k n e g y _ k e y Now just: ...

If you’re still typing ssh -i ~/.ssh/mykey.pem ec2-user@ec2-54-123-45-67.compute-1.amazonaws.com, you’re working too hard. SSH config transforms verbose commands into simple ssh prod invocations. The Basics Create or edit ~/.ssh/config: H o s t H U I p o s d r s e e o t r n d N t a e i m c t e 2 y - F 5 u i 4 s l . e e 1 r 2 ~ 3 / . . 4 s 5 s . h 6 / 7 p r o d - k e y . p e m Now ssh prod connects with the right key and user. No more remembering IP addresses. ...

SSH tunnels are one of those tools that seem magical until you understand the three basic patterns. Once you do, you’ll use them constantly. The Three Types Local forwarding (-L): Access a remote service as if it were local Remote forwarding (-R): Expose a local service to a remote network Dynamic forwarding (-D): Create a SOCKS proxy through the SSH connection Let’s break down each one. Local Forwarding: Reach Remote Services Locally Scenario: You need to access a database that’s only available from a server you can SSH into. ...

If you’re still typing ssh -i ~/.ssh/my-key.pem -p 2222 admin@192.168.1.50 every time you connect, you’re doing it wrong. The SSH config file is one of the most underutilized productivity tools in a developer’s arsenal. The Basics: ~/.ssh/config Create or edit ~/.ssh/config: 1 2 3 4 5 Host dev HostName dev.example.com User deploy IdentityFile ~/.ssh/deploy_key Port 22 Now you just type ssh dev. That’s it. Host Patterns Wildcards let you apply settings to multiple hosts: ...

If you’re still typing ssh -i ~/.ssh/prod-key.pem -p 2222 ubuntu@ec2-54-123-45-67.compute-1.amazonaws.com, you’re working too hard. SSH config files let you define aliases with all your connection details. Basic Config Create or edit ~/.ssh/config: H o s t H U P I p o s o d r s e r e o t r t n d N t a u 2 i m b 2 t e u 2 y n 2 F e t i c u l 2 e - 5 ~ 4 / - . 1 s 2 s 3 h - / 4 p 5 r - o 6 d 7 - . k c e o y m . p p u e t m e - 1 . a m a z o n a w s . c o m Now connect with just: ...

SSH is the workhorse of remote access. But most people only scratch the surface. Here’s how to use it like a pro. SSH Config: Stop Typing So Much Instead of: 1 ssh -i ~/.ssh/prod-key.pem -p 2222 ubuntu@ec2-54-123-45-67.compute-1.amazonaws.com Create ~/.ssh/config: H H H o o o s s s t t t H U P I H U I F P U p o s o d s o s d o r s r s e r e t s e e r . o e o t r t n a t r n w i x r d N t g N t a n y a u 2 i i a d i r t J a m b 2 t n m e t d e u d e u 2 y g e p y A r m m n 2 F l F g n p i e t i s o i e a n c u l t y l n l b 2 e a e t a - g s 5 ~ i ~ y t 4 / n / e i - . g . s o 1 s . s n 2 s e s 3 h x h - / a / 4 p m s 5 r p t - o l a 6 d e g 7 - . i . k c n c e o g o y m - m . k p p e u e y t m . e p - e 1 m . a m a z o n a w s . c o m Now just: ...