Firewall Wizards mailing list archives
Re: ICMP Packets.
From: Andrew Yeomans <andrew_yeomans () uk ibm com>
Date: Wed, 3 Jun 1998 12:46:08 +0000
The IBM Redbook "Protect and Survive Using IBM Firewall 3.1 for AIX", IBM publication SG24-2577-02 has a good discussion on ICMP packets in section 3.1.2 and 6.20. This is not specific to the IBM product. You can find the book on-line, plus ordering details, at http://www.redbooks.ibm.com, use the top-left search panel to look for "protect and survive". Unfortunately the pictures in 6.20 have not been uploaded to the on-line book. They are described in section 3.1.2, but to help you out, these are the summarised rules from 6.20 pictures: Action Packet type ICMP type Direction ------ ----------- --------- --------- Permit ICMP echo request type 8 code 0 Secure<->FW, FW<->Nonsecure Permit ICMP echo reply type 0 code 0 Secure<->FW, FW<->Nonsecure Block ICMP echo request type 8 code 0 All directions Block ICMP echo reply type 0 code 0 All directions Permit outgoing redirect type 5 code any Secure<--FW, FW-->Nonsecure Block ICMP redirect type 5 code any All directions Permit dest unreachable type 3 code any Secure<->FW, FW<--Nonsecure Block dest unreachable type 3 code any All directions Permit source quench type 4 code any Secure<->FW, FW<->Nonsecure Permit time exceeded type 11 code any Secure<->FW, FW<--Nonsecure Permit time exceeded type 11 code any Secure---routed-->Nonsecure Block time exceeded type 11 code any All directions Permit parameter problem type 12 code any Secure<->FW, FW<->Nonsecure Block all ICMP type any code any All directions These are to be read sequentially, so the "block" rules mop up any exceptions to the earlier permit rules. Note carefully the direction arrows. These all assume a dual-homed firewall configuration. Do read the text too, as it has some differences to the rules above from the pictures, with explanations. Andrew_Yeomans () uk ibm com, Installation Support Centre, EMEA Network Computing Software and e-business Centre of Competence, MP 3GS, IBM UK Ltd, 1 New Square, Bedfont Lakes, Feltham, Middlesex,TW14 8HB Tel: +44-181-818-4288 Int: 36-4288 Fax: +44-181-818-5475 Pager: 01523-494985 "A program that has not been specified cannot be incorrect, it can only be surprising."
Current thread:
- Re: ICMP Packets., (continued)
- Re: ICMP Packets. Bennett Todd (Jun 04)
- Re: ICMP Packets. Darren Reed (Jun 05)
- Re: ICMP Packets. tqbf (Jun 07)
- Re: ICMP Packets. Darren Reed (Jun 07)
- Re: ICMP Packets. blast (Jun 08)
- Re: ICMP Packets. Aleph One (Jun 09)
- Re: ICMP Packets. Ge' Weijers (Jun 05)
- Re: ICMP Packets. Bennett Todd (Jun 05)
- Re: ICMP Packets. tqbf (Jun 04)
- Re: ICMP Packets. Paul D. Robertson (Jun 05)
- Re: ICMP Packets.uy tqbf (Jun 07)
- Re: ICMP Packets. Henry Hertz Hobbit (Jun 07)
- Re: ICMP Packets. tqbf (Jun 07)
- Re: ICMP Packets. Aleph One (Jun 12)