[CentOS] Re: slow SMTP-AUTH
Ray Van Dolson
rvandolson at esri.com
Wed Jul 25 23:39:48 UTC 2007
On Wed, Jul 25, 2007 at 07:35:58PM -0400, Ugo Bellavance wrote:
> Ugo Bellavance wrote:
> >Brett Schroeder wrote:
> >>Ugo Bellavance wrote:
> >>> I installed sendmail on a centos-4 openvz VM. I set up SMTP-AUTH
> >>>and when I try to send mail using this server, there is a big delay in
> >>>which my e-mail client (Mozilla Thunderbird) just hangs. The server, on
> >>>the other hand, is idle at the same time. It does that no matter if I
> >>>use no encryption, TLS, or SSL. When the client is 'hung' sendmail, on
> >>>the server side haven't logged anything yet for this connection.
> >>>Any idea?
> >>Since nothing is logged on the server, it sounds like there is a
> >>firewall (or
> >>other networking problem) in the way. You should use WireShark (or
> >>tcpdump) on
> >>the client to capture the network traffic.
> I disabled the firewall on the server, no luck. I tried sniffing, I see
> nothing weird.
> 5.512292 22.214.171.124 -> 126.96.36.199 TCP 17274 > submission [PSH,
> ACK] Seq=350 Ack=10923 Win=17461 Len=53
> 5.512984 188.8.131.52 -> 184.108.40.206 TCP submission > 17274 [PSH,
> ACK] Seq=10923 Ack=403 Win=7504 Len=277
> 5.724172 220.127.116.11 -> 18.104.22.168 TCP 17274 > submission [ACK]
> Seq=403 Ack=11200 Win=17184 Len=0
> 22.884013 22.214.171.124 -> 126.96.36.199 TCP 17274 > submission [PSH,
> ACK] Seq=403 Ack=11200 Win=17184 Len=53
> 22.884918 188.8.131.52 -> 184.108.40.206 TCP submission > 17274 [PSH,
> ACK] Seq=11200 Ack=456 Win=7504 Len=85
> 22.970714 220.127.116.11 -> 18.104.22.168 TLSv1 Application Data
> 22.971120 22.214.171.124 -> 126.96.36.199 TLSv1 Application Data
Can you run strace on sendmail during a connection and see what it's
doing? DNS is often the culprit when delays are concerned, so look for
anything along those lines.
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