Blocking IP on one of the interfaces?

Question

Computer networks

I have a Mikrotik router. 2 providers are connected to it: provider A (ISP1) and provider B (ISP2). It is necessary to block IP on provider B so that the specified IP does not ping through this interface. And on the ISP1 interface, the ping was fine.

Answer 1

/ip firewall filter add chain=input protocol=icmp action=drop in-interface=ISP2 \
  src-address=11.22.33.44

Where ISP2 is the name of the interface looking at provider B, and 11.22.33.44 is the IP that needs to be denied ping.
But this would be nicer:

/ip firewall filter add chain=input protocol=icmp action=drop in-interface=ISP2 \
  src-address-list=DENY-PING
/ip firewall address-list add list=DENY-PING address=11.22.33.44

The rule must be above the allow rule:

/ip firewall filter print 
...
1     ;;; Deny ping
     chain=input protocol=icmp action=drop in-interface=ISP2 src-address-list=DENY-PING
2     ;;; Allow ping
      chain=input action=accept protocol=icmp
...

Answer 2

A little chaotically written, of course, but if we are talking about the fact that the internal client would go to the specified IP through a specific provider, then this is decided by routing to the desired interface, and not by blocking rules.