[__sa__nya]

Уже нашел ответ. По умолчанию ICMPv4 типа echo request разрешены в ufw:

Enabling ufw creates a ruleset that is intended to protect the host while allowing some common traffic such as DHCP, ping and mDNS. These defaults are setup in the before*.rules and after*.rules files (see 'man iptables' for terminology): - Default DROP on INPUT - Default DROP on FORWARD - Default ACCEPT on OUTPUT - ACCEPT all on lo - DROP packets with RH0 headers - ACCEPT all RELATED and ESTABLISHED on INPUT and OUTPUT - ACCEPT all RELATED and ESTABLISHED on FORWARD (ip forwarding must be enabled via sysctl for this to be in effect) - DROP INVALID packets (packets not associated with a known connection) - ACCEPT certain icmp packets (INPUT and FORWARD): - destination-unreachable, source-quench, time-exceeded, parameter-problem, and echo-request for IPv4 - destination-unreachable, packet-too-big, time-exceeded, parameter-problem, and echo-request - ACCEPT certain icmpv6 packets for stateless autoconfiguration (INPUT): neighbor-solicitation, neighbor-advertisement, router-solicitation - ACCEPT mDNS (zeroconf/bonjour/avahi 224.0.0.251 for IPv4 and ff02::fb for IPv6) for service discovery (INPUT) - ACCEPT UPnP (239.255.255.250 for IPv4 and ff02::f for IPv6) for service discovery (INPUT) - ACCEPT ping replies from IPv6 link-local (ffe8::/10) addresses (INPUT) - ACCEPT DHCP client traffic (INPUT) - Log all blocked packets not matching the default policy with rate limiting If you are using a packaged version of ufw supplied by your distribution, the default ruleset may be different.

Не совсем это конечно удобно. Удобнее когда отключил абсолютно все, а потом нужные параметры включаешь. Понял так что этот функционал дает iptables, но он якобы сложнее в настройке. Почитаю.