smtp not working with state modulation

[Mark Pagulayan]

Hi Guys, 

 

OS: FreeBSD 7.0-RELEASE

 

I am having trouble Allowing external request SMTP through the firewall
with "module state". But with "keep state" it is working fine. 

Here is my rules below in pf:

 

ext_if="em1"

int_if="em0"

 

scrub in on $ext_if

 

block in log on $ext_if all

block return out log on $ext_if all

 

pass in log quick on $int_if

pass out log quick on $int_if

 

pass log quick on $ext_if proto tcp from any to 192.168.1.1 port 25
modulate state flags S/SA

 

block in log quick on $ext_if proto tcp from any to any port 25

 

 

When I to try to telnet from my PC(192.169.1.2) 

telnet 192.168.1.1 25

I get "Connection Failed" Error.

 

Checking on the tcpdump on interface pflog0, here is what is shows.

========================================================================
=======================

[root at fw4 /home/mark]# tcpdump -netti pflog0  port 25

tcpdump: WARNING: pflog0: no IPv4 address assigned

tcpdump: verbose output suppressed, use -v or -vv for full protocol
decode

listening on pflog0, link-type PFLOG (OpenBSD pflog file), capture size
96 bytes

 

1210641823.095857 rule 4/0(match): pass in on em1: 192.168.1.2.2573 >
192.168.1.1.25:  tcp 28 [bad hdr length 0 - too short, < 20]

 

========================================================================
============================

 

Your help would be mostly appreciated. 

 

Cheers, 

 

Mark