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Accepted
Frank Martin
Asked: 2017-08-06 07:46:22 +0800 CST

Why is ping working when all incoming and outgoing connections are blocked in the firewall?

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I have DENIED both incoming and outgoing connections using ufw on Debian VPS. There is only one rule defined, which is to allow connection to SSH port.

ufw is enabled and working.

Yet I am still able to ping from my laptop to server using its IP. Why is ping still working if both incoming and outgoing connections are blocked (except SSH)?

debian

1 Answers

  1. Best Answer

    Ping is ICMP so there's no TCP/UDP connections to block or accept (and that's what you probably denied). ICMP rules are configured in /etc/ufw/before.rules.

    See this for more information.

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