From owner-freebsd-questions@freebsd.org Thu Feb 20 15:20:16 2020 Return-Path: Delivered-To: freebsd-questions@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id A5C6B23C102 for ; Thu, 20 Feb 2020 15:20:16 +0000 (UTC) (envelope-from news@mips.inka.de) Received: from mail.inka.de (mail.inka.de [IPv6:2a04:c9c7:0:1073:217:a4ff:fe3b:e77c]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 48NdZ72HcJz4D5N for ; Thu, 20 Feb 2020 15:20:15 +0000 (UTC) (envelope-from news@mips.inka.de) Received: from mips.inka.de (news@[127.0.0.1]) by mail.inka.de with uucp (rmailwrap 0.5) id 1j4ncU-0004i9-Bm; Thu, 20 Feb 2020 16:20:06 +0100 Received: from lorvorc.mips.inka.de (localhost [127.0.0.1]) by lorvorc.mips.inka.de (8.15.2/8.15.2) with ESMTP id 01KFJhbN023863 for ; Thu, 20 Feb 2020 16:19:43 +0100 (CET) (envelope-from news@lorvorc.mips.inka.de) Received: (from news@localhost) by lorvorc.mips.inka.de (8.15.2/8.15.2/Submit) id 01KFJhkL023862 for freebsd-questions@freebsd.org; Thu, 20 Feb 2020 16:19:43 +0100 (CET) (envelope-from news) To: freebsd-questions@freebsd.org From: Christian Weisgerber Newsgroups: list.freebsd.questions Subject: Re: tightening sshd, removing server identification banner Date: Thu, 20 Feb 2020 15:19:43 -0000 (UTC) Message-ID: References: User-Agent: slrn/1.0.3 (FreeBSD) X-Rspamd-Queue-Id: 48NdZ72HcJz4D5N X-Spamd-Bar: +++ Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=none (mx1.freebsd.org: domain of news@mips.inka.de has no SPF policy when checking 2a04:c9c7:0:1073:217:a4ff:fe3b:e77c) smtp.mailfrom=news@mips.inka.de X-Spamd-Result: default: False [3.37 / 15.00]; ARC_NA(0.00)[]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; TO_DN_NONE(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[freebsd-questions@freebsd.org]; AUTH_NA(1.00)[]; RCPT_COUNT_ONE(0.00)[1]; RCVD_COUNT_THREE(0.00)[3]; RCVD_TLS_LAST(0.00)[]; NEURAL_SPAM_MEDIUM(0.87)[0.872,0]; NEURAL_SPAM_LONG(0.85)[0.850,0]; DMARC_NA(0.00)[inka.de]; R_SPF_NA(0.00)[]; FORGED_SENDER(0.30)[naddy@mips.inka.de,news@mips.inka.de]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:202113, ipnet:2a04:c9c7::/32, country:DE]; FROM_NEQ_ENVFROM(0.00)[naddy@mips.inka.de,news@mips.inka.de]; IP_SCORE(0.45)[ip: (1.19), ipnet: 2a04:c9c7::/32(0.60), asn: 202113(0.48), country: DE(-0.02)] X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 20 Feb 2020 15:20:16 -0000 On 2020-02-17, David Mehler wrote: > I'm running FreeBSD 12.0. I'm atempting to tighten up my sshd > configuration. I've got things where I want them, except for the > connecting banner. I'm using sshaudit.com to test things and this is > what it's saying for the banner setting: > > Banner:SSH-2.0-OpenSSH_7.8 FreeBSD-20180909 > > I would rather this be set to nothing or at most very minimal. RFC4253 says the identification string MUST be SSH-protoversion-softwareversion SP comments CR LF where only "comments" is optional. I also recommend a look at src/crypto/openssh/compat.c to gain some appreciation that "softwareversion" is important. -- Christian "naddy" Weisgerber naddy@mips.inka.de