iptables and apt

[Jan Tammen <jan.tammen@et-inf.fho-emden.de>]

Hi,
I set up the following rules to allow ftp with my iptables-based
packetfilter:

iptables -A INPUT -i $PPP_IFACE -p tcp ! --syn --sport 20 --dport \
$UNPRIVPORTS -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -A INPUT -i $PPP_IFACE -p tcp ! --syn --sport 21 --dport \
$UNPRIVPORTS -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -A INPUT -i $PPP_IFACE -p tcp ! --syn --dport 20 -j ACCEPT \
iptables -A INPUT -i $PPP_IFACE -p tcp --dport 21 -j ACCEPT

Where PPP_IFACE is my external interface an UNPRIVPORTS = 1024:65535.
Trying to update my box via apt-get (on the 'firewall'-host), the 
connection to the server is not established and I get these errors:

IN=ippp0 OUT= MAC= SRC=141.76.2.4 DST=217.224.116.100 LEN=60 TOS=0x00 \
PREC=0x00 TTL=54 ID=0 DF PROTO=TCP SPT=48685 DPT=1141 WINDOW=5712 \
RES=0x00 ACK SYN URGP=0
...

What to do?
-- 
"it's not so simple being simple" | http://tammen.net/jt/