On Wed, Sep 23, 2009 at 4:29 PM, Wietse Venema <[email protected]> wrote:
> Reinaldo de Carvalho:
>> Hi,
>>
>> Someone can tell me why EHLO reply send 2 packets?
>>
>> ~# postconf  mail_version
>> mail_version = 2.5.5
>>
>>
>> ## tcpdump ##
>>
>> ^[OM^[OM15:41:23.546763 IP 10.15.10.9.49898 > 10.15.1.65.25: P 1:10(9)
>> ack 34 win 46 <nop,nop,timestamp 927636169 259345475>
>> e.....@[email protected].
>> .
>>
>> ..A....`.[TU.s............
>> 7J...uLCEHLO myhost.example.com
>
> Above is "EHLO myhost.example.com" from the SMTP client to the SMTP server.
>
>> 15:41:23.546924 IP 10.15.1.65.25 > 10.15.10.9.49898: . ack 10 win 91
>> <nop,nop,timestamp 259346474 927636169>
>> e.....@.?..9
>> ..A
>> .
>>         ....U.s.`.[]...[.......
>> .uP*7J..
>
> Above is a TCP acknowledgment from server kernel to client kernel.
>

Verify "MAIL FROM packet" from my the first, or any other SMTP stage,
postfix reply only one packet.

# Connection handshake + SMTP Banner
16:46:04.084849 IP 10.15.10.9.44807 > 10.15.1.65.25: S
1432841543:1432841543(0) win 5840 <mss 1460,sackOK,timestamp 928606106
0,nop,wscale 7>
16:46:04.085172 IP 10.15.1.65.25 > 10.15.10.9.44807: S
2235726686:2235726686(0) ack 1432841544 win 5792 <mss
1460,sackOK,timestamp 260316627 928606106,nop,wscale 6>
16:46:04.085241 IP 10.15.10.9.44807 > 10.15.1.65.25: . ack 1 win 46
<nop,nop,timestamp 928606106 260316627>
16:46:04.085928 IP 10.15.1.65.25 > 10.15.10.9.44807: P 1:34(33) ack 1
win 91 <nop,nop,timestamp 260316627 928606106>
16:46:04.085951 IP 10.15.10.9.44807 > 10.15.1.65.25: . ack 34 win 46
<nop,nop,timestamp 928606106 260316627>

# EHLO + 2 reply packets
16:46:12.709990 IP 10.15.10.9.44807 > 10.15.1.65.25: P 1:12(11) ack 34
win 46 <nop,nop,timestamp 928608262 260316627>
16:46:12.710163 IP 10.15.1.65.25 > 10.15.10.9.44807: . ack 12 win 91
<nop,nop,timestamp 260318784 928608262>
16:46:12.710236 IP 10.15.1.65.25 > 10.15.10.9.44807: P 34:174(140) ack
12 win 91 <nop,nop,timestamp 260318784 928608262>
16:46:12.710261 IP 10.15.10.9.44807 > 10.15.1.65.25: . ack 174 win 54
<nop,nop,timestamp 928608262 260318784>

# MAIL FROM + reply packet
16:46:19.395992 IP 10.15.10.9.44807 > 10.15.1.65.25: P 12:37(25) ack
174 win 54 <nop,nop,timestamp 928609934 260318784>
16:46:19.396554 IP 10.15.1.65.25 > 10.15.10.9.44807: P 174:188(14) ack
37 win 91 <nop,nop,timestamp 260320456 928609934>
16:46:19.396602 IP 10.15.10.9.44807 > 10.15.1.65.25: . ack 188 win 54
<nop,nop,timestamp 928609934 260320456>

# RCPT TO + reply packet
16:46:29.729985 IP 10.15.10.9.44807 > 10.15.1.65.25: P 37:66(29) ack
188 win 54 <nop,nop,timestamp 928612518 260320456>
16:46:29.734784 IP 10.15.1.65.25 > 10.15.10.9.44807: P 188:202(14) ack
66 win 91 <nop,nop,timestamp 260323041 928612518>
16:46:29.734839 IP 10.15.10.9.44807 > 10.15.1.65.25: . ack 202 win 54
<nop,nop,timestamp 928612519 260323041>

# DATA + reply packet
16:46:32.672287 IP 10.15.10.9.44807 > 10.15.1.65.25: P 66:71(5) ack
202 win 54 <nop,nop,timestamp 928613253 260323041>
16:46:32.672525 IP 10.15.1.65.25 > 10.15.10.9.44807: P 202:239(37) ack
71 win 91 <nop,nop,timestamp 260323775 928613253>
16:46:32.672580 IP 10.15.10.9.44807 > 10.15.1.65.25: . ack 239 win 54
<nop,nop,timestamp 928613253 260323775>


-- 
Reinaldo de Carvalho
http://korreio.sf.net
http://python-cyrus.sf.net

"Don't try to adapt the software to the way you work, but rather
yourself to the way the software works" (myself)

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