[Xymon] Xymon - smtp

Jeremy Laidman jeremy at laidman.org
Wed Mar 28 08:00:12 CEST 2018


The default timeout for xymonnet is 10 seconds. The xymonnet command in
tasks.cfg can have "--timeout=N" added to adjust timeouts.

Have you tried to connect to the service yourself, using telnet, to see if
there is indeed a timeout, and what form it takes? Something like this:

$ printf "mail\r\nquit\r\n" | time nc ipxdvo.tcif.telstra.com.au. 25

or if you don't have nc or netcat:

$ { printf "mail\r\nquit\r\n"; sleep 1; } | time telnet qts-pro-cm-weber 25

Xymon has more than one form of timeout. I believe if Xymon fails to
connect due to a timeout, it will show a different error to what you've
seen. In your case, I suspect Xymon has connected, and has issued its
commands (mail and quit, from protocols.cfg), and is waiting for "220". If
it doesn't get a 220 within 10 seconds, it will timeout the session.

I've seen this type of thing happen when TCP wrappers are used to limit
access to a service, or for similar security measures. In these cases, the
incoming connection is from a host that the mail server does not know
about, and so it attempts to find the hostname by reverse DNS lookup. If
DNS is slow or misconfigured on the mail server, the DNS lookup can take 15
seconds to fail. In these cases, a quick fix is to add the Xymon server IP
address to the /etc/hosts file on the mail server. A better solution is to
fix the DNS.

J


On 28 March 2018 at 07:27, Ajay Kumar Talla <atalla at zetaglobal.com> wrote:

> Thank you for the information.
>
> But I don’t see any huge CPU  load on my server for the past 4 hours. But
> still SMTP test is flapping.
>
> The screenshot attached says “*connection timedout*” is there a way to
> change the time-out setting?
>
>
>
> I have the same SMTP test on another server whose Load becomes high at
> times, but it’s SMTP remains green.
>
>
>
> *From:* Root, Paul T <Paul.Root at CenturyLink.com>
> *Sent:* Wednesday, March 28, 2018 1:42 AM
> *To:* Root, Paul T <Paul.Root at CenturyLink.com>; Ajay Kumar Talla <
> atalla at zetaglobal.com>; xymon at xymon.com
> *Subject:* RE: Xymon - smtp
>
>
>
>
>
> https://serverfault.com/questions/119026/question-on-
> sendmail-daemon-actions-when-load-average-is-too-high
> <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fserverfault.com%2Fquestions%2F119026%2Fquestion-on-sendmail-daemon-actions-when-load-average-is-too-high&data=02%7C01%7Catalla%40zetaglobal.com%7C5184c4e69cfc41d611ff08d5941f037d%7C47049324c4984be5acf70154448a1107%7C1%7C0%7C636577783282992025&sdata=gTT%2BrA7A88BosFDvteurJlcdKSi7XiT1ug6l%2FSd5zPg%3D&reserved=0>
>
>
>
> *From:* Xymon [mailto:xymon-bounces at xymon.com <xymon-bounces at xymon.com>] *On
> Behalf Of *Root, Paul T
> *Sent:* Tuesday, March 27, 2018 3:10 PM
> *To:* 'Ajay Kumar Talla'; xymon at xymon.com
> *Subject:* Re: [Xymon] Xymon - smtp
>
>
>
> This is a load issue. Sendmail will refuse to process mail messages if the
> CPU is too busy.
>
>
>
> *From:* Xymon [mailto:xymon-bounces at xymon.com <xymon-bounces at xymon.com>] *On
> Behalf Of *Ajay Kumar Talla
> *Sent:* Tuesday, March 27, 2018 12:59 PM
> *To:* xymon at xymon.com
> *Subject:* [Xymon] Xymon - smtp
>
>
>
> Hi,
>
>
>
> I’m using smtp test in Xymon for monitoring. However sometimes, I’m
> getting error as connection timed out.  After sometime it is showing as
> Green(Flapping status)
>
>
>
>
>
> Could you please, let me know the solution for this.
>
>
>
> Thanks,
>
> Ajay
>
> This communication is the property of CenturyLink and may contain
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> by reply e-mail and destroy all copies of the communication and any
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>
> This communication is the property of CenturyLink and may contain
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