IPFW with NAT : Problems with duplicate packets on FreeBSD 10.3-RC3

[Dr Josef Karthauser]

> On 8 Apr 2016, at 06:51, Ian Smith <smithi at nimnet.asn.au> wrote:
> 
> On Thu, 7 Apr 2016 17:08:38 +0100, Dr Josef Karthauser wrote:
> 
> [ AppleMail msgs fail to quote properly in pine, so a partial quote: ]
> 
>> Looks like the first packet is being retransmitted, which means that 
>> the nat is probably misconfigured and the TCP connection is broken in
>> some strange way.
> 
>> Does anyone have a clue as to where to look? The ipfw rules are
>> simple enough - what have I missed?
> 
> Do you have TSO enabled on that NIC?  If so, see ipfw(8) BUGS, third 
> last para.  If not, no idea ..
> 

Thanks Ian,

It was exactly that issue! I wish I had remembered that I’d seen that in the man page; would have saved hours of debugging :)

Joe

— 
Dr Josef Karthauser
Chief Technical Officer
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