[rescue] sdf.org and HP-97 [was Re: New to the list - PDP-8 fan]

[Mouse]

>>> I have an HP-97 calculator here that I would like to unload, [...]

>> You're a hard mouse to reach.  Your mail server rejects GMail by
>> rule, which I can understand.

Yeah, Google has earned themselves the dubious honour of the hardest
email block I know how to throw up. :-(

>> I tried again my from sdf.org account, and received:

>>     ----- Transcript of session follows -----
>> ... while talking to mx-4.rodents-montreal.org.:
>> <<< 550-I won't talk to 205.166.94.24 until 2021-09-22 01:36:22 UTC, because
>> <<< 550 it keeps connecting and then not sending anything.
>> 554 5.0.0 Service unavailable

Thank you for quoting the details; with that I should be able to find
it in my logs.

*search*  Yup.

Turns out mx.sdf.org, which appears to be their outgoing mailhost as
well as their incoming MX host, drops the connection slightly over 50
seconds into my banner delay, a point at which all the SMTP specs agree
any client-side timeout should be at least five minutes (eg, see RFC
5321 section 4.5.3.2.1).  Here's an example from my logs, before the
"you're failing too consistently" ban kicked in:

2021-09-20 21:07:11.10: [RDfzfH.DCQC.ZbD] (21155) connection from 205.166.94.24/60244
2021-09-20 21:07:11.10: [RDfzfH.DCQC.ZbD] found 205.166.94.24, cleared 0, now: ban 0, past 0
2021-09-20 21:07:11.10: [RDfzfH.DCQC.ZbD] crosschecking 205.166.94.24
2021-09-20 21:07:11.10: [RDfzfH.DCQC.ZbD] doing PTR query for 24.94.166.205.in-addr.arpa
2021-09-20 21:07:11.10: [RDfzfH.DCQC.ZbD] response, ancount=1
2021-09-20 21:07:11.10: [RDfzfH.DCQC.ZbD] answer record 0 name 24.94.166.205.in-addr.arpa
2021-09-20 21:07:11.10: [RDfzfH.DCQC.ZbD] found PTR for 24.94.166.205.in-addr.arpa
2021-09-20 21:07:11.10: [RDfzfH.DCQC.ZbD] got PTR: mx.sdf.org
2021-09-20 21:07:11.10: [RDfzfH.DCQC.ZbD] doing A query for mx.sdf.org
2021-09-20 21:07:11.10: [RDfzfH.DCQC.ZbD] response, ancount=1
2021-09-20 21:07:11.10: [RDfzfH.DCQC.ZbD] answer record 0 name mx.sdf.org
2021-09-20 21:07:11.10: [RDfzfH.DCQC.ZbD] found A for mx.sdf.org
2021-09-20 21:07:11.10: [RDfzfH.DCQC.ZbD] got A for mx.sdf.org: cda65e18 (matches)
2021-09-20 21:07:11.17: [RDfzfH.DCQC.ZbD] check_pool_name: mx.sdf.org
2021-09-20 21:07:11.17: [RDfzfH.DCQC.ZbD] doing ident query: 60244,25
2021-09-20 21:07:11.24: [RDfzfH.DCQC.ZbD] connect: Connection refused
2021-09-20 21:08:01.13: [RDfzfH.DCQC.ZbD] drop delay 50.032279
2021-09-20 21:08:01.13: [RDfzfH.DCQC.ZbD] unexpected SMTP connection drop
2021-09-20 21:08:01.13: [RDfzfH.DCQC.ZbD] ban_add_ratelimit nullconn: val 53116
2021-09-20 21:08:01.13: [RDfzfH.DCQC.ZbD] done

I don't know whether they've picked software written by someone who
didn't know the spec, couldn't be bothered to implement it correctly,
or maybe they just misconfigured a setting, or what.

>> I'm interested in the HP-97.

There's someone I'm waiting for a mailing address from.  Unless I get
fed up waiting for that (which would take days), the HP-97 is already
spoken for.

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