You could do some sort of template to generate iptables-restore format and refresh it every so often (once an hour, or day). Yes, dyamic DNS is fairly common on application layer firewalls. That said, they don't run in the kernel and their resolvers are fairly good at caching that info... Running things through proxy servers or other things can allow you to make your rules use dns names there. PS: I would assume that the "DNS" requirement is only for external services that publish by DNS name only and not for internal services or gateway services that publish the IP to use outside of DNS. On Tue, Nov 13, 2012 at 11:32 AM, /dev/rob0 <rob0@xxxxxxxxx> wrote: > On Tue, Nov 13, 2012 at 11:18:55AM -0500, Greg Folkert wrote: >> I'm being told by my PCI QSA that IPTables supports DNS Names in kernel. > > You obviously know this is wrong. > >> He is forcing me to use "DNS Names" in my "iptables-restore" formatted >> save file. I am using a Fedora (FC2) based Firewall (with some updated >> packages to fix things)... its quite Old... (which they also don't like) >> using IPTables v1.2.9. >> >> The problem is, IPTables only deals with "IP Addresses" in its structure >> and doesn't have "dynamic" IP resolution and only resolves on >> "runtime/load". Now if I use "iptables-save" the file format does NOT in >> fact use DNS and only dumps the IP Address. >> >> What I need is the actual documentation that seems TERRIBLY hard to find >> on this very subject... > > The iptables(8) manual: > " > [!] -s, --source address[/mask][,...] > Source specification. Address can be either a network name, a > hostname, a network IP address (with /mask), or a plain IP > address. Hostnames will be resolved once only, before the rule > is submitted to the kernel. Please note that specifying any name > to be resolved with a remote query such as DNS is a really bad > idea. ... > " > > The iptables-restore(8) manual is very short and does not cover these > specifics, but it does refer to iptables in "SEE ALSO". And perhaps a > patch would be accepted. :) > >> He is also claiming that other firewalls solutions (aka Proprietary, aka >> Cisco) "dynamically" resolve rules... which I believe is incorrect, as >> well. > > I don't know Cisco et al, but I don't see how this would be practical > without some kind of backend to monitor DNS for changes and update a > list of IP addresses. > > (You could do the same thing with iptables and ipset(8), FWIW, albeit > not so easily on your Fedorasaurus, of course.) > >> Please point me at some place I can find "authoritative" documentation >> for this situation for me to either "suck it up" or to give him direct >> docs for him to include in our Audit. >> >> Thanks. Hopefully I have stated the issue well enough. > > Good luck. > -- > http://rob0.nodns4.us/ -- system administration and consulting > Offlist GMX mail is seen only if "/dev/rob0" is in the Subject: > -- > To unsubscribe from this list: send the line "unsubscribe netfilter" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
