[LUNI] firewall problem

[Boex,Matthew W.]

i am running rh6.1, ipchains, at home as my firewall.  i have a web server
behind it running apache.  when i try to access my web server from our proxy
at work, i sometimes get an error saying i am using http when i should be
using https.  now, from the tcpdump below, it's looks to me like my firewall
is switching the ports.  this doesn't happen everytime, which baffles me.
below is a good attempt, then a bad one.  why would my firewall do this?
does someone have an example of ipchains rules that will allow for http and
https servers?

good try

16:34:30.616613 eth0 < out.cna.com.56837 > computer.www: tcp 0 (DF)
16:34:30.616879 eth1 > out.cna.com.56837 > rootabega.www: tcp 0 (DF)
16:34:30.617503 eth1 < rootabega.www > out.cna.com.56837: tcp 0 (DF)
...

bad try

16:43:00.658569 eth0 < out.cna.com.38845 > computer.www: tcp 0 (DF)
16:43:00.658812 eth1 > out.cna.com.38845 > rootabega.https: tcp 0 (DF)
16:43:00.659401 eth1 < rootabega.https > out.cna.com.38845: tcp 0 (DF)

...

matt