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Date:      13 Jun 1999 19:33:21 +0200
From:      Dag-Erling Smorgrav <des@flood.ping.uio.no>
To:        Jay Nelson <jdn@acp.qiv.com>
Cc:        security@FreeBSD.ORG
Subject:   Re: Connection attempts to port 7
Message-ID:  <xzpzp24rony.fsf@flood.ping.uio.no>
In-Reply-To: Jay Nelson's message of "Sun, 13 Jun 1999 12:25:47 -0500 (CDT)"
References:  <Pine.BSF.4.05.9906131218430.678-100000@acp.qiv.com>

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Jay Nelson <jdn@acp.qiv.com> writes:
> Recently, I've been getting _many_ attempts to connect to the echo
> service (which I have disabled) -- mostly non-resolvable addresses
> that disappear somewhere behind doubleclick.net.

If the source address is spoofed, it's not a connection attempt, but a
syn flood. Set up a firewall to drop connection attempts to all ports
except those you want to keep open. This won't help if the attacker
finds out and switches to a port you want to keep open; if that
happens, install the SYN rate limiting patch which was posted here a
while ago (search the BUGTRAQ archives on www.geek-girl.com).

> Does anyone know of a legitimate reason why they would do this?

No.

DES
-- 
Dag-Erling Smorgrav - des@flood.ping.uio.no


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