On 2003-02-25 16:09, Joshua Lokken <[EMAIL PROTECTED]> wrote:
> When I remove the default deny rule from the list, nat works fine,
> port redirections and all, but with the deny rule in place, nat
> isn't working, so I'm thinking I have a rule in the wrong place.
> Can anyone point out any obvious missing/misplaced rules here?

For NAT to be working, you hav to make sure natd(8) is running and has
a proper configuration file.

Now, as far as the ipfw(8) rules are concerned, try using the
following ruleset:

# $fwcmd -f flush
# $fwcmd add allow all from any to any via lo0
# $fwcmd add divert natd all from any to any via $oif
# $fwcmd add allow icmp from any to any icmptypes 3,4,11,12
# $fwcmd add check-state
# $fwcmd add allow udp from $oip to any via $oif keep-state
# $fwcmd add allow tcp from any to $oip 22,80,443,6346,22002,22003,22010 setup via 
$oif keep-state
# $fwcmd add allow ip from $oip to any keep-state out via $oif
# $fwcmd add allow ip from $inwr to any keep-state via $iif
# $fwcmd add 65435 deny log ip from any to any

The changes from your own set of rules are summarized below:

  - moved icmp checking higher, since they're unrelated to tcp or udp
    and state checking

  - added a rule for udp packets, since DNS resolving and a few other
    useful things depend on them

  - moved check-state higher, to minimise the delay for packets that
    are parts of an existing connection (ipfw rules are checked
    sequentially, from start to end)

  - added keep-state in your 'setup' rule for incoming connections to
    $oip and 'via $oif' to make sure that packets destined for $oip
    are only accepted on $oif (good measure against spoofing)

Before using this set of rules, make sure you give proper values to
$iip, $oip, $iif, $oif and $inwr.

- Giorgos

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