Skip site navigation (1)Skip section navigation (2)
Date:      Tue, 15 Jun 1999 16:56:49 +0200
From:      Juergen Nickelsen <ni@tellique.de>
To:        sporkl@ix.netcom.com
Cc:        freebsd-security@FreeBSD.ORG
Subject:   Re: firewalls
Message-ID:  <376669B1.F7E6A746@tellique.de>
References:  <Pine.BSF.4.05.9906121112550.6023-100000@pigstuy.penguinpowered.com>

next in thread | previous in thread | raw e-mail | index | archive | help
Spike wrote:

> Which are appropriate to block?

On my own firewall, I let pass the ICMP types

  0     Echo Reply                               [RFC792]
  3     Destination Unreachable                  [RFC792]
  4     Source Quench                            [RFC792]
  8     Echo                                     [RFC792]
 11     Time Exceeded                            [RFC792]
 12     Parameter Problem                        [RFC792]
 13     Timestamp                                [RFC792]
 14     Timestamp Reply                          [RFC792]
 15     Information Request                      [RFC792]
 16     Information Reply                        [RFC792]
 17     Address Mask Request                     [RFC950]
 18     Address Mask Reply                       [RFC950]
 30     Traceroute                              [RFC1393]
 31     Datagram Conversion Error               [RFC1475]

(excerpted from RFC 1700)

For completeness, these are the other types that are blocked:

  1     Unassigned                                  [JBP]
  2     Unassigned                                  [JBP]
  5     Redirect                                 [RFC792]
  6     Alternate Host Address                      [JBP]
  7     Unassigned                                  [JBP]
  9     Router Advertisement                    [RFC1256]
 10     Router Selection                        [RFC1256]
 19     Reserved (for Security)                    [Solo]
 20-29  Reserved (for Robustness Experiment)        [ZSu]
 32     Mobile Host Redirect              [David Johnson]
 33     IPv6 Where-Are-You                 [Bill Simpson]
 34     IPv6 I-Am-Here                     [Bill Simpson]
 35     Mobile Registration Request        [Bill Simpson]
 36     Mobile Registration Reply          [Bill Simpson]
 37-255 Reserved                                    [JBP]

I am not *really* sure if this is all ok, and I would appreciate a
more authoritative response.

Greetings, Juergen.

-- 
Juergen Nickelsen <ni@tellique.de>
Tellique Kommunikationstechnik GmbH
Gustav-Meyer-Allee 25, 13355 Berlin, Germany
Tel. +49 30 46307-552 / Fax +49 30 46307-579


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-security" in the body of the message




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?376669B1.F7E6A746>