A Working RouterOS Firewall Input Chain, Line by Line
Six rules that decide what can reach the router itself, in the order they must run — and the one rule every tutorial leaves out that makes the rest mean anything.
Networking · TIBCO · Unix
Vendor defaults ship enabled and stay invisible. Every guide here is run against equipment I operate, with the commands, the actual output, and what to do when the documentation and the device disagree.
[admin@gw-edge] > /ip service print where disabled=no # NAME PORT 0 telnet 23 1 ftp 21 2 www 80 3 ssh 22 4 api 8728 FAILtelnet, ftp, www and api reachableenabled by default — plaintext credentials [admin@gw-edge] > /tool mac-server print FAILMAC-Telnet allowed on all interfacesbypasses every firewall rule you wrote [admin@gw-edge] > /ip neighbor discovery-settings print FAILdiscovery advertising on the WANmodel, RouterOS version, identity — to anyone [admin@gw-edge] > /tool bandwidth-server print FAILbandwidth-test server accepting sessionsa CPU exhaustion primitive, on by default 4 findings. None appear in /export. NET · MikroTik RouterOS · Cisco IOS
Hardening, firewall design, and the defaults that ship enabled but never appear in an export.
Six rules that decide what can reach the router itself, in the order they must run — and the one rule every tutorial leaves out that makes the rest mean anything.
A failed import leaves everything before the bad line applied and abandons the rest. The error tells you a line number and nothing about what landed.
Patching RouterOS closed the door but never removed what came through it. Six checks that find the accounts, scripts and proxies a compromise leaves behind.
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