1 src 2 dest
Thu, 26 Jul 2001 18:13:14 -0400
I just read the patch-o-matic SAME help and it says that it is
similar to SNAT: it takes a range
of addresses and gives a client the same address for each connection.
Looks like I was either wrong
or else I simply don't understand the use of the SAME target. Does
anybody have a slightly clearer
> Duplicate and resending packets is not sufficent:I'll try to explain:
> in a tcp connection there are some numbers choosen by each host used
> in the 3way handshake.
> Duiplicating a packet will send 2 syn packets with he same ack numer
> to 2 different host. Each host will reply with one ack number. The
> first that reaches the sender host will be accepted and using in the
> last part of the handshake, the other will be discarder because isn't
> related to any known connection (the ack number is not correct...).
> This doesn't mean that one mail will be delivered:I think that NO mai
> will be delivered.
> Brad Chapman wrote:
>> Mr. Schaaf,
>> Huh? I seemed to have read about a SAME target which allowed you to
>> duplicate and resend packets to a different IP address. I believe it
>> performs exactly what this guy wants: to be able to deliver multiple
>> e-mails to different servers. The only drawback, AFAICE, is that it
>> requires multiple rules for multiple e-mail servers; however, AFAIK,
>> multiple-delivery SMTP server you describe could fix that
>> Patrick Schaaf wrote:
>>>> so for example if I had a mail server on the outside of a iptables
>>>> firewall, and I sendmail to this mail server, I want same mail
>>>> delieved to that server and another mail server aswell.
>>> This cannot be done at a packet filtering level. You could use the
>>> REDIRECT rules to capture the outgoing SMTP connection, handle it
>>> using an SMTP server on the firewall machine, and write this SMTP
>>> server in a way that stably feeds each outgoing mail to the two
>>> external servers (essentially duplicating the mail, and running
>>> two independant deliveries). I don't know of any SMTP server
>>> software capable of doing that out of the box, so you probably
>>> have to find a knowledgeable programmer who writes it for you.
>>> For a competent person, that should 1-2 man-weeks work.