Specific sites not accepting 'postings' from a browser IPT 1.2.2 kernel 2.4.5 (patched)

[Alistair Tonner]

	*sighs*

   I hate having to ask, as I'd much rather figure this out myself, but
here goes.

  previously used ipchains with the same physical configuration and NO
problems.

  Now: kernel 2.4.5
            iptables 1.2.2 (from download + install + patch o matic)
  	    X 4.0.3 (the reason for the kernel/firewall change *grin* do
get DRI)
	
	  I have two rules in the iptables set I am using at the moment, 

	iptables -A POSTROUTING -t nat -s $INTERNALNET -o ppp0 -j
MASQUERADE
	iptables -A FORWARD -o ppp0 -p tcp --tcp-flags SYN,RST SYN -m
tcpmss --mss \
            1493: -j TCPMSS --set-mss 1492

        The first is the masquerade to get the downstream winders boxen
online, which pretty much
	appears to work well except for this issue.
	The second line is due to us being on PPPoE (Sympatico.ca) 
	The MTU for PPPoE is dependent on the fact that the ethernet pipe
size is 1500 and you 
	have to have 8 for the PPP packet inside the ethernet frame.

	The specific sites involved are www.renderosity.com and
www.3dcommune.com.
	The posts from IE on the downstream winders box start fine, and the
browser actually 
	sends enough data that it appears the transfer has gone through
(byte count from iptraf
	compared to actual file sizes of subject files) however the end
result of the transfer is 
	a 'Server hangup' or 'page cannot be found'  --- the results are
similar in netscape on 
	winders -- although it is more consistently Server hangups.
  	
	My other half is getting exceedingly upset with my Linux
implementation and this is starting
	to really annoy me.  The interesting note is that she can post one
line postings to her online 
	journal site, however anything much more than 20 words (appx 65 to
80 characters total)
	recieves the same error (Server hangup or page not found) .. I
assume (perhaps incorrectly) that
	this is some sort of server redirection occurring, however I am
unsure from the acres of reading 	
	that I've been doing as to how to cure this issue.  

	Anyone who helps me will have the undying affection of a redhead
learning how to use poser 4 
	(My other half *grin*)

	Alistair Tonner
	Direct responses accepted at Atonner(at)Hotpop.com