I've just upgrade a server from debian squeeze to debian wheezy, using a
custom config file i use in my servers; i've changed a little the config
file, mostly adding STARTTLS with auth.
The server accept SMTP connection in lan, and in the same LAN there's no
network trouble, or at least other bandwith-hungry app/proto (samba, ...)
does not complain.
I've tried with a client (Thunderbird ESR latest version, Windows 7) and a
tshark dump depicted:
0.000000 10.27.2.25 -> 10.27.1.3 TCP 66 49989 > 587 [SYN] Seq=0 Win=8192 Len=0 MSS=1460 WS=256 SACK_PERM=1
0.000019 10.27.1.3 -> 10.27.2.25 TCP 66 587 > 49989 [SYN, ACK] Seq=0 Ack=1 Win=14600 Len=0 MSS=1460 SACK_PERM=1 WS=128
0.000384 10.27.2.25 -> 10.27.1.3 TCP 60 49989 > 587 [ACK] Seq=1 Ack=1 Win=65536 Len=0
5.001534 10.27.1.3 -> 10.27.2.25 SMTP 127 S: 220 stregatto.pp.lnf.it ESMTP Exim 4.80 Thu, 11 Jun 2015 15:25:59 +0200
5.003000 10.27.2.25 -> 10.27.1.3 SMTP 73 C: EHLO [10.27.2.25]
5.003069 10.27.1.3 -> 10.27.2.25 TCP 54 587 > 49989 [ACK] Seq=74 Ack=20 Win=14720 Len=0
5.003407 10.27.1.3 -> 10.27.2.25 SMTP 184 S: 250-stregatto.pp.lnf.it Hello [10.27.2.25] [10.27.2.25] | 250-SIZE 26214400 | 250-8BITMIME | 250-PIPELINING | 250-STARTTLS | 250 HELP
5.004375 10.27.2.25 -> 10.27.1.3 SMTP 64 C: STARTTLS
note the 5 seconds between the TCP handshake and the SMTP banner printout.
I've tried with or without STARTTLS, with or without auth, and the 5 second
delay still is present.
DNS seems to work very well (resolve correctly back and forth the client).
The strage thing is that, if i try to send a mail with thunderbird, same
version, on Linux (ubuntu 64bit) there's no delay:
0.000000 10.27.1.14 -> 10.27.1.3 TCP 74 35365 > 587 [SYN] Seq=0 Win=29200 Len=0 MSS=1460 SACK_PERM=1 TSval=5240983 TSecr=0 WS=128
0.000028 10.27.1.3 -> 10.27.1.14 TCP 74 587 > 35365 [SYN, ACK] Seq=0 Ack=1 Win=14480 Len=0 MSS=1460 SACK_PERM=1 TSval=451415683 TSecr=5240983 WS=128
0.000213 10.27.1.14 -> 10.27.1.3 TCP 66 35365 > 587 [ACK] Seq=1 Ack=1 Win=29312 Len=0 TSval=5240983 TSecr=451415683
0.001432 10.27.1.3 -> 10.27.1.14 SMTP 139 S: 220 stregatto.pp.lnf.it ESMTP Exim 4.80 Thu, 11 Jun 2015 15:50:25 +0200
0.001627 10.27.1.14 -> 10.27.1.3 TCP 66 35365 > 587 [ACK] Seq=1 Ack=74 Win=29312 Len=0 TSval=5240983 TSecr=451415683
0.010328 10.27.1.14 -> 10.27.1.3 SMTP 85 C: EHLO [10.27.1.14]
0.010400 10.27.1.3 -> 10.27.1.14 TCP 66 587 > 35365 [ACK] Seq=74 Ack=20 Win=14592 Len=0 TSval=451415685 TSecr=5240985
0.010743 10.27.1.3 -> 10.27.1.14 SMTP 196 S: 250-stregatto.pp.lnf.it Hello [10.27.1.14] [10.27.1.14] | 250-SIZE 26214400 | 250-8BITMIME | 250-PIPELINING | 250-STARTTLS | 250 HELP
0.011341 10.27.1.14 -> 10.27.1.3 SMTP 76 C: STARTTLS
Someone can give me a clue on how to debug that issue? I really don't now
where to hit my head...
Thanks.
--
``... La memoria conta veramente solo se tiene insieme l'impronta del
presente e il progetto del futuro, se permette di fare senza dimenticare
quel che si voleva fare, di diventare senza smettere di essere,
di essere senza smettere di diventare...'' (Italo Calvino)
