2.99.50s19 smtp & hotmail.com

[Michael Smith <michael@csuite.ns.ca>]

We're using ZMailer 2.99.50s19 compiled with egcs-1.1.2 on Solaris 2.7.
Since the upgrade (from 2.99.50s11) our smtp transport agents have started
hanging after connecting to hotmail and sending several messages. Until
someone notices and kills the hung ta, no more mail goes through to
Hotmail. Here are some log excerpts:

(process 18939 is already connected to mail.hotmail.com[216.33.151.135|25])
1893970063150898#       jobspec: B/34061-16574  hotmail.com
1893970063250898#       34061-16574:
<Pine.GSO.3.95.iB1.0.990701133738.18900A-101000@halifax.chebucto.ns.ca>
1893970063350899w       MAIL From:<xxxxx@chebucto.ns.ca>
1893970063450902r       250 Requested mail action okay, completed
1893970063550902w       RCPT To:<xxxxx@hotmail.com>
1893970063650906r       250 Requested mail action okay, completed
1893970063750906w       DATA
1893970063850906r       354 Start mail input; end with <CRLF>.<CRLF>
1893970063950955#       (closed SMTP channel - appendlet() failure, status=-999)
1893970064050955#       (closed SMTP channel - after delivery failure)

(ok, maybe Hotmail hung up on us, so it connects again)

1893970064150955#       (Connecting to `mail.hotmail.com' [216.33.151.135|25] Thu Jul  1 14:42:35 1999)
1893970064250955#       localidentity=halifax.chebucto.ns.ca bind() errno = 0
1893970064350959r       220-HotMail (NO UCE) ESMTP server ready at Thu Jul
01 10:42:47 1999 
1893970064450959r       220 ESMTP spoken here
1893970064550959w       EHLO halifax.chebucto.ns.ca
1893970064650959r       500 Syntax error, command unrecognized
1893970064750959w       HELO halifax.chebucto.ns.ca
1893970064850959r       250 Requested mail action okay, completed

[snip a successful delivery, and 6 more]

1893970073451494r       250 Requested mail action okay, completed
1893970073551494#       679 bytes, 1562 in header, 1 recipients, 296 secs
for envelope, 0 secs for body xfer
1893970073651494#       jobspec: P/33997-16576  hotmail.com
1893970073751494#       33997-16576:
<Pine.GSO.3.95.iB1.0.990701141626.27652D-100000@halifax.chebucto.ns.ca>
1893970073851494w       MAIL From:<yyyyy@chebucto.ns.ca>
1893970073951498r       250 Requested mail action okay, completed
1893970074051498w       RCPT To:<yyyyy@hotmail.com>
1893970074151507r       250 Requested mail action okay, completed
1893970074251507w       DATA
1893970074351516r       354 Start mail input; end with <CRLF>.<CRLF>
1893970074451516w       .
1893970074551517r       250 Requested mail action okay, completed
1893970074651517#       730 bytes, 1180 in header, 1 recipients, 22 secs
for envelope, 1 secs for body xfer
1893970074751517w       MAIL From:<yyyyy@chebucto.ns.ca>
1893970074851521r       250 Requested mail action okay, completed
1893970074951521w       RCPT To:<zzzzz@hotmail.com>
1893970075051539r       250 Requested mail action okay, completed
1893970075151539w       DATA
1893970075251549r       354 Start mail input; end with <CRLF>.<CRLF>
1893970075351549w       .
1893970075451549r       250 Requested mail action okay, completed
1893970075551549#       730 bytes, 1180 in header, 1 recipients, 32 secs
for envelope, 0 secs for body xfer
1893970075651730w       NOOP
1893970075751730r       421 Service not available, closing transmission channel.
1893970075851730w       QUIT
1893970075951730#       (closed SMTP channel - hangup on smtpwrite() )

Now the ta just hangs. truss -p 18939 shows it's polling something (argh,
it just scrolled out of the backbuffer...).

Any idea what's going wrong?