continued IPFW issues... (actually a lack of ability on my part)
jez.hancock at munk.nu
Sat Feb 14 16:59:31 PST 2004
On Sat, Feb 14, 2004 at 05:59:14PM -0600, Eric F Crist wrote:
> On Sat, Feb 14, 2004 at 03:27:35PM -0600, Eric F Crist wrote:
> > I'm still having some sort of issues with ipfw rules on my server.
> > I've got a
> > cgi based irc client installed, and I can't connect. Also, it seems
> as if my
> > DNS server isn't able to send queries out. An ipfw show displays the
> > following for me:
> > 00050 54632 4640473 allow ip from me to any
> > 00100 0 0 allow ip from any to any via lo0
> > 00200 0 0 deny ip from any to 127.0.0.0/8
> > 00300 0 0 deny ip from 127.0.0.0/8 to any
> > 00400 4027 351563 allow ip from 22.214.171.124/29 to me
> > 00500 2 80 allow ip from any to me dst-port 22
> > 00600 2 80 allow ip from any to me dst-port 21
> > 00700 388 25405 allow ip from any to me dst-port 25
> > 00800 58 4944 allow ip from any to me dst-port 80
> > 00900 2 80 allow ip from any to me dst-port 443
> > 01000 2 80 allow ip from any to me dst-port 110
> > 01100 54 4247 allow ip from any to me dst-port 53
> > 01200 2 80 allow ip from any to me dst-port 6667
> > 01300 2 80 allow ip from any to me dst-port 6668
> > 01400 4 160 deny ip from not 126.96.36.199/29 to me dst-port
> > 65535 46432 7224466 deny ip from any to any
> > Where is all that denied traffic coming from on the final rule?
> You are only allowing traffic in and not out - as Matthew Seaman
> mentioned in the last post in your previous thread, you should use
> 'keep-state' to keep track of the connections made to you. See the
> examples he provided in that thread.
> >From the manpage for ipfw:
> Checks the packet against the dynamic ruleset. If a match
> found, execute the action associated with the rule which
> ated this dynamic rule, otherwise move to the next rule.
> Check-state rules do not have a body. If no check-state
> rule is
> found, the dynamic ruleset is checked at the first
> keep-state or
> limit rule.
> Upon a match, the firewall will create a dynamic rule,
> default behaviour is to match bidirectional traffic between
> source and destination IP/port using the same protocol.
> The rule
> has a limited lifetime (controlled by a set of sysctl(8)
> ables), and the lifetime is refreshed every time a matching
> packet is found.
> When a connection is made to port 80 from an external host, with the
> 'keep-state' flag set on your rule for port 80 data transfer will be
> allowed in both directions to/from the external host to/from you on port
> 80 for a limited period. The check-state rule effectively 'shortcuts'
> the rest of the rules in the ruleset if a match is made for the external
> host for the given action (inbound connections to port 80 in this case).
> You'd need to do the same for each of the other ports you want to allow
> free connections to/from.
> Wouldn't my first rule:
> ipfw allow ip from me to any
> have fixed this problem?
Sorry I missed that rule :( How about adding a log keyword to that last
deny rule temporarily just to see what exactly is being denied?
- System Administrator / PHP Developer
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