Re: iSCSI: SendTargets & NAT

[Bill Studenmund <wrstuden@wasabisystems.com>]

On Tue, 30 Apr 2002, Julian Satran wrote:

> Bill - you may want to read the NDT draft and the relevant part on the
> system structure assumption in chapter 2.

Julio, you may want to double check the documents you send me to read
before you choose to suggest I read something rather than comment on
points I make. I reviewed chapter 2, and found nothing that really touches
the point I'm trying to raise. Actually, when I read the NDT document,
Appendix B.1 actually agrees with the point I'm trying to make.  :-)

> Target addresses are not used directly in the protocol and even accessing
> beyond a NAT you start by setting-up a TCP connection to what you think is
> the address.

Putting numeric IP addresses in the TargetAddress response constitutes a
direct use of target addresses in the protocol. Do you disagree?

Also, plesae think a bit about what you said just above. "You start by
setting-up a TCP connection to what you think is the address." What if
none of the numeric addresses returned by TargetAddress is the one you
contacted? You obviously have one IP that will work, but you don't know
what else is available at that IP.

To quote NDT B.1,

         -  iSCSI messages that specify a particular initiator or target,
            such as login requests and third party requests, should specify
            the initiator or target in a location-independent manner.  This
            is accomplished using the iSCSI Name.

With NAT around, numeric IP addresses aren't location-independent. :-)

Please note exactly what I'm suggesting be added.

I'm *NOT* suggesting we get rid of having numberic IPs. Since what
TargetAddress returns is probably what was configured by an admin, if an
admin does something that's not NAT friendly, oh well. Plus for a lot of
uses, numeric IPs will probably be fine.

What I am suggesting is that we add an optional way to say, "use the IP
address you just contacted me at." The initiator should know what IP that
is, and this is a way of the target saying, "keep using it."

I'm also suggesting something like "*" be the symbol used to say, "at this
IP address."

Thoughts?

Take care,

Bill