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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spamd-Bar: --- X-Spamd-Result: default: False [-3.89 / 15.00]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-1.00)[-1.000]; DMARC_POLICY_ALLOW(-0.50)[plan-b.pwste.edu.pl,quarantine]; R_SPF_ALLOW(-0.20)[+mx]; R_DKIM_ALLOW(-0.20)[plan-b.pwste.edu.pl:s=plan-b-mailer]; MIME_GOOD(-0.10)[text/plain]; ONCE_RECEIVED(0.10)[]; XM_UA_NO_VERSION(0.01)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; RCVD_COUNT_ONE(0.00)[1]; ASN(0.00)[asn:206006, ipnet:2001:678:618::/48, country:PL]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_ALL(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; MLMMJ_DEST(0.00)[freebsd-net@freebsd.org]; FROM_HAS_DN(0.00)[]; HAS_XAW(0.00)[]; ARC_NA(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; TO_DN_NONE(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[freebsd-net@freebsd.org]; DKIM_TRACE(0.00)[plan-b.pwste.edu.pl:+] X-Rspamd-Queue-Id: 4VYn4n2l06z4pnF W dniu 7.05.2024 o 20:12, Ed Maste pisze: > I propose that we start dropping inbound ICMP REDIRECTs by default, by > setting the net.inet.icmp.drop_redirect sysctl to 1 by default (and > changing the associated rc.conf machinery). I've opened a Phabricator > review at https://reviews.freebsd.org/D45102. > > ICMP REDIRECTs served a useful purpose in earlier networks, but on > balance are more likely to represent a security issue today than to > provide a routing benefit. With the change in review it is of course > still possible to enable them if desired for a given installation. > This change would appear in FreeBSD 15.0 and would not be MFC'd. > > One question raised in the review is about switching the default to > YES but keeping the special handling for "auto" (dropping ICMP > REDIRECT if a routing daemon is in use, honouring them if not). I > don't think this is particularly valuable given that auto was > introduced to override the default NO when necessary; there's no need > for it with the default being YES. That functionality could be > maintained if there is a compelling use case, though. > > If you have any questions or feedback please follow up here or in the review. > Thank you for submitting your inquiry to the community. I spotted it on Phabricator yesterday. It looks to me like a long-awaited, positive change. But what about IPv6 ? We have "net.inet6.icmp6.rediraccept" knob which defaults to 1. Can ICMPv6 redirects be fixed along with the change proposed for the legacy IP protocol? -- Marek Zarychta