Bruteforce login prevention MIkrotik

(Redirected from Bruteforce login prevention (FTP & SSH))

To stop SSH/FTP attacks on your router, follow this advice.

This configuration allows only 10 FTP login incorrect answers per minute

in /ip firewall filter

add chain=input protocol=tcp dst-port=21 src-address-list=ftp_blacklist
 action=drop \ comment="drop ftp brute forcers"

add chain=output action=accept protocol=tcp content="530 Login incorrect" 
dst-limit=1/1m,9,dst-address/1m

add chain=output action=add-dst-to-address-list protocol=tcp 
content="530 Login incorrect" \
address-list=ftp_blacklist address-list-timeout=3h

This will prevent a SSH brute forcer to be banned for 10 days after repetitive attempts. Change the timeouts as necessary.

in /ip firewall filter

add chain=input protocol=tcp dst-port=22 
src-address-list=ssh_blacklist action=drop \ 
comment="drop ssh brute forcers" disabled=no


add chain=input protocol=tcp dst-port=22 connection-state=new \
src-address-list=ssh_stage3 action=add-src-to-address-list
address-list=ssh_blacklist \ address-list-timeout=10d 
comment="" disabled=no



add chain=input protocol=tcp dst-port=22 connection-state=new \
src-address-list=ssh_stage2 action=add-src-to-address-list 
address-list=ssh_stage3 \ address-list-timeout=1m comment="" disabled=no



add chain=input protocol=tcp dst-port=22 connection-state=new 
src-address-list=ssh_stage1 \ action=add-src-to-address-list 
address-list=ssh_stage2 address-list-timeout=1m comment="" disabled=no



add chain=input protocol=tcp dst-port=22 connection-state=new 
action=add-src-to-address-list \ address-list=ssh_stage1 
address-list-timeout=1m comment="" disabled=no

If you want to block downstream access as well, you need to block the with the forward chain:

add chain=forward protocol=tcp dst-port=22 
src-address-list=ssh_blacklist action=drop \ 
comment="drop ssh brute downstream" disabled=no

To view the contents of your Blacklist, go to "/ip firewall address-list" and type "print" to see the contents.

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