thanks a lot jozsef
delleceste at gmail.com
Mon Sep 12 20:15:48 CEST 2005
Thanks a lot Jozsef for your answer to the news about my question about a
comment on tcp window.
The precious hint you gave me is that i don't need to play with seq/ack!
So, if i understood well, i don't need to worry about window sizes as well,
to do simple nat...
I was quite sure about those things, but the problem is that my nat works
fine if i call an Internet Service Provider,
but if I call another one, web sites and images are corrupted and things
don't work well...
i tried to lower mtu, and tried with the rule "clamp-tcpmss-to-pmtu", but
did not solve.
Then i tried to see if packets arrived fragmented and so lost in nat, but a
printk put in netfilter code,
wher defrag takes place, revealed that packets were not fragmented.
Now i'm quite desperate, cause i don't know where to look for an answer!
Could it be that i use bad functions to recalculate checksum? But why with
an ISP that works
while with the other not?
I use ip_fast_csum() for ip, and
tcp_v4_check(transport_header, skb->len-4*iph->ihl, saddr, daddr,
csum_partial( transp_header, skb->len-4*iph->ihl, 0) )
for tcp/udp chacksum.
tcpdump always says it's correct.
Thanks for your help and any other suggestions!
Giacomo S, Italy
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