What Is Causing This Failure

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What Is Causing This Failure

Carlwill
I am getting a report from someone on my network that they are getting
delivery failures when attempting to send an email from my Postfix
server to the remote mail server. I see  the message stuck on my
Postfix servers queue:

CB87E778055     1337 Mon Nov 30 08:59:15  [hidden email]
               (connect to a.mx.premore.net[198.186.193.20]: No route to host)
                                         [hidden email]

I am guessing that this is a problem with the remote mail server
'a.mx.premore.net' since my server is sending and receiving email just
fine to every other destination. I then decided to do a MX lookup for
this domain "premore.net" & see if there is anything wrong:

;; QUESTION SECTION:
;premore.net. IN MX

;; ANSWER SECTION:
premore.net. 3093 IN MX 0 a.mx.premore.net.

;; ADDITIONAL SECTION:
a.mx.premore.net. 3093 IN A 198.186.193.20

However my mail server wont send to this destination address and I
have no idea why. Can someone tell me how I can better examine this
situation to understand where the fault lies.

Thank you!
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Re: What Is Causing This Failure

Eero Volotinen-2
Carlos Williams wrote:

> CB87E778055     1337 Mon Nov 30 08:59:15  [hidden email]
>                (connect to a.mx.premore.net[198.186.193.20]: No route to host)

> However my mail server wont send to this destination address and I
> have no idea why. Can someone tell me how I can better examine this
> situation to understand where the fault lies.

Well, check your internet connectivity. No route to host means that
server cannot connect to other end. (you can test using telnet
ip.address 25)

Usually netmask/gateway or firewall is poorly configured or your isp is
blocking direct smtp connections without smarthost.

--
Eero
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Re: What Is Causing This Failure

erol blakely
In reply to this post by Carlwill
On Tue, Dec 01, 2009 at 10:03:21AM -0500, Carlos Williams wrote:
 
> CB87E778055     1337 Mon Nov 30 08:59:15  [hidden email]
>                (connect to a.mx.premore.net[198.186.193.20]: No route to host)
>                                          [hidden email]

Looks like more of a network issue and not postfix specific.

Try to telnet to the remote host and see if you can connect (run a
tcpdump at the same time to see whats happening). Try simple
network diagnostics (ie. ping, traceroute etc ...).

/erol
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Re: What Is Causing This Failure

Ralf Hildebrandt
In reply to this post by Carlwill
* Carlos Williams <[hidden email]>:
> I am getting a report from someone on my network that they are getting
> delivery failures when attempting to send an email from my Postfix
> server to the remote mail server. I see  the message stuck on my
> Postfix servers queue:
>
> CB87E778055     1337 Mon Nov 30 08:59:15  [hidden email]
>                (connect to a.mx.premore.net[198.186.193.20]: No route to host)
>                                          [hidden email]

Works OK. What does tracroute 198.186.193.20 return?
# traceroute 198.186.193.20
traceroute to 198.186.193.20 (198.186.193.20), 30 hops max, 60 byte packets
... snip ...
 4  zr-pot1-te0-0-0-3.x-win.dfn.de (188.1.144.30)  5.288 ms  5.290 ms 5.281 ms
 5  cr02.frf02.pccwbtn.net (80.81.192.50)  18.030 ms  18.027 ms 18.132 ms
 6  carpathia.ge12-1.br02.ash01.pccwbtn.net (63.218.94.166)  109.111 ms  106.313 ms  106.528 ms
 7  xe-3-3.e4.iad1.cirn.net (209.222.130.29)  105.968 ms  106.036 ms 106.044 ms
 8  66.117.37.180 (66.117.37.180)  101.005 ms  100.773 ms  101.520 ms
  9  * * *
  10  * * *
  11  * * *
  12  * * *
  13  * * *
  14  * * *
  15  * * *
  16  * * *
  17  * * *
  18  * * *
  19  * * *
  20  * * *
  21  * * *
  22  * * *
  23  * * *
  24  * * *
  25  dns5.docforge.org (198.186.193.20)  4.241 ms  1.685 ms  0.271 ms
 

> I am guessing that this is a problem with the remote mail server
> 'a.mx.premore.net' since my server is sending and receiving email just
> fine to every other destination. I then decided to do a MX lookup for
> this domain "premore.net" & see if there is anything wrong:
>
> ;; QUESTION SECTION:
> ;premore.net. IN MX
>
> ;; ANSWER SECTION:
> premore.net. 3093 IN MX 0 a.mx.premore.net.
>
> ;; ADDITIONAL SECTION:
> a.mx.premore.net. 3093 IN A 198.186.193.20
>
> However my mail server wont send to this destination address and I
> have no idea why. Can someone tell me how I can better examine this
> situation to understand where the fault lies.
>
> Thank you!

--
Ralf Hildebrandt
  Geschäftsbereich IT | Abteilung Netzwerk
  Charité - Universitätsmedizin Berlin
  Campus Benjamin Franklin
  Hindenburgdamm 30 | D-12203 Berlin
  Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962
  [hidden email] | http://www.charite.de
           
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Re: What Is Causing This Failure

Martijn de Munnik-2
In reply to this post by Carlwill
On Tue, 2009-12-01 at 10:03 -0500, Carlos Williams wrote:
> I am getting a report from someone on my network that they are getting
> delivery failures when attempting to send an email from my Postfix
> server to the remote mail server. I see  the message stuck on my
> Postfix servers queue:
>
> CB87E778055     1337 Mon Nov 30 08:59:15  [hidden email]
>                (connect to a.mx.premore.net[198.186.193.20]: No route to host)
>                                          [hidden email]
>

This is a network issue and not a postfix issue. Try connecting to
a.mx.premore.net using telnet on port 25.
Check your routing tables to find out why a network connection to that
host is not possible.

> I am guessing that this is a problem with the remote mail server
> 'a.mx.premore.net' since my server is sending and receiving email just
> fine to every other destination. I then decided to do a MX lookup for
> this domain "premore.net" & see if there is anything wrong:
>
> ;; QUESTION SECTION:
> ;premore.net. IN MX
>
> ;; ANSWER SECTION:
> premore.net. 3093 IN MX 0 a.mx.premore.net.
>
> ;; ADDITIONAL SECTION:
> a.mx.premore.net. 3093 IN A 198.186.193.20
>
> However my mail server wont send to this destination address and I
> have no idea why. Can someone tell me how I can better examine this
> situation to understand where the fault lies.
>
> Thank you!


--
Martijn de Munnik <[hidden email]>
YoungGuns

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Re: What Is Causing This Failure

Ralf Hildebrandt
In reply to this post by Carlwill
* Evan Platt <[hidden email]>:

> Unless I'm misreading and misunderstanding your logs....
>
> # telnet 198.186.193.20 25
> Trying 198.186.193.20...
> telnet: connect to address 198.186.193.20: Operation timed out
> telnet: Unable to connect to remote host
>
> The mail server on that IP isn't answering.

# telnet 198.186.193.20 25
Trying 198.186.193.20...
Connected to 198.186.193.20.
Escape character is '^]'.
220 share.docforge.org ESMTP Postfix

--
Ralf Hildebrandt
  Geschäftsbereich IT | Abteilung Netzwerk
  Charité - Universitätsmedizin Berlin
  Campus Benjamin Franklin
  Hindenburgdamm 30 | D-12203 Berlin
  Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962
  [hidden email] | http://www.charite.de
           
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Re: What Is Causing This Failure

Carlwill
In reply to this post by Ralf Hildebrandt
On Tue, Dec 1, 2009 at 10:10 AM, Ralf Hildebrandt
<[hidden email]> wrote:

> Works OK. What does tracroute 198.186.193.20 return?
> # traceroute 198.186.193.20
> traceroute to 198.186.193.20 (198.186.193.20), 30 hops max, 60 byte packets
> ... snip ...
>  4  zr-pot1-te0-0-0-3.x-win.dfn.de (188.1.144.30)  5.288 ms  5.290 ms 5.281 ms
>  5  cr02.frf02.pccwbtn.net (80.81.192.50)  18.030 ms  18.027 ms 18.132 ms
>  6  carpathia.ge12-1.br02.ash01.pccwbtn.net (63.218.94.166)  109.111 ms  106.313 ms  106.528 ms
>  7  xe-3-3.e4.iad1.cirn.net (209.222.130.29)  105.968 ms  106.036 ms 106.044 ms
>  8  66.117.37.180 (66.117.37.180)  101.005 ms  100.773 ms  101.520 ms
>  9  * * *
>  10  * * *
>  11  * * *
>  12  * * *
>  13  * * *
>  14  * * *
>  15  * * *
>  16  * * *
>  17  * * *
>  18  * * *
>  19  * * *
>  20  * * *
>  21  * * *
>  22  * * *
>  23  * * *
>  24  * * *
>  25  dns5.docforge.org (198.186.193.20)  4.241 ms  1.685 ms  0.271 ms

I am unable to connect via Telnet so it appears to be a network / ISP issue.

carlos@tunafish:~$ telnet 198.186.193.20 25
Trying 198.186.193.20...
telnet: Unable to connect to remote host: No route to host
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Re: What Is Causing This Failure

Ralf Hildebrandt
* Carlos Williams <[hidden email]>:

> >  25  dns5.docforge.org (198.186.193.20)  4.241 ms  1.685 ms  0.271 ms
>
> I am unable to connect via Telnet so it appears to be a network / ISP issue.
>
> carlos@tunafish:~$ telnet 198.186.193.20 25
> Trying 198.186.193.20...
> telnet: Unable to connect to remote host: No route to host

What is the output of traceroute 198.186.193.20 ?
--
Ralf Hildebrandt
  Geschäftsbereich IT | Abteilung Netzwerk
  Charité - Universitätsmedizin Berlin
  Campus Benjamin Franklin
  Hindenburgdamm 30 | D-12203 Berlin
  Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962
  [hidden email] | http://www.charite.de
           
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Re: What Is Causing This Failure

Carlwill
On Tue, Dec 1, 2009 at 10:43 AM, Ralf Hildebrandt
<[hidden email]> wrote:
> What is the output of traceroute 198.186.193.20 ?

I get no results from my mail server:

traceroute to 198.186.193.20 (198.186.193.20), 30 hops max, 40 byte packets
 1  * * *
 2  * * *
 3  * * *
 4  * * *
 5  * * *
.
.
.
29  * * *
30  * * *

Strange...
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Re: What Is Causing This Failure

Frog-5
Perhaps your mail server is on a DNSBL?

Regards
Frog


----- Original Message -----
From: "Carlos Williams" <[hidden email]>
To: [hidden email]
Sent: Tuesday, 1 December, 2009 4:05:25 PM
Subject: Re: What Is Causing This Failure

On Tue, Dec 1, 2009 at 10:43 AM, Ralf Hildebrandt
<[hidden email]> wrote:
> What is the output of traceroute 198.186.193.20 ?

I get no results from my mail server:

traceroute to 198.186.193.20 (198.186.193.20), 30 hops max, 40 byte packets
 1  * * *
 2  * * *
 3  * * *
 4  * * *
 5  * * *
.
.
.
29  * * *
30  * * *

Strange...

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Re: What Is Causing This Failure

Martijn de Munnik-2
On Tue, 2009-12-01 at 16:27 +0000, Frog wrote:
> Perhaps your mail server is on a DNSBL?
>
> Regards
> Frog

Nope, this is a problem at the ip level, routing. This is not a postfix
or mail/smtp issue.

> ----- Original Message -----
> From: "Carlos Williams" <[hidden email]>
> To: [hidden email]
> Sent: Tuesday, 1 December, 2009 4:05:25 PM
> Subject: Re: What Is Causing This Failure
>
> On Tue, Dec 1, 2009 at 10:43 AM, Ralf Hildebrandt
> <[hidden email]> wrote:
> > What is the output of traceroute 198.186.193.20 ?
>
> I get no results from my mail server:
>
> traceroute to 198.186.193.20 (198.186.193.20), 30 hops max, 40 byte packets
>  1  * * *
>  2  * * *
>  3  * * *
>  4  * * *
>  5  * * *
> .
> .
> .
> 29  * * *
> 30  * * *
>
> Strange...
>



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Re: What Is Causing This Failure

Terry Inzauro
In reply to this post by Frog-5
Frog wrote:

> Perhaps your mail server is on a DNSBL?
>
> Regards
> Frog
>
>
> ----- Original Message -----
> From: "Carlos Williams" <[hidden email]>
> To: [hidden email]
> Sent: Tuesday, 1 December, 2009 4:05:25 PM
> Subject: Re: What Is Causing This Failure
>
> On Tue, Dec 1, 2009 at 10:43 AM, Ralf Hildebrandt
> <[hidden email]> wrote:
>> What is the output of traceroute 198.186.193.20 ?
>
> I get no results from my mail server:
>
> traceroute to 198.186.193.20 (198.186.193.20), 30 hops max, 40 byte packets
>  1  * * *
>  2  * * *
>  3  * * *
>  4  * * *
>  5  * * *
> .
> .
> .
> 29  * * *
> 30  * * *
>
> Strange...
>

why all the off topic posts today?


-----------------------

chances are a router along the way is not forwarding icmp probes/responses correctly......

[10:39:23 root@allover:~]# tcptraceroute 198.186.193.20 25
Selected device eth0, address 10.123.0.250, port 56230 for outgoing packets
Tracing the path to 198.186.193.20 on TCP port 25 (smtp), 30 hops max
 1  10.123.0.252  0.302 ms  0.133 ms  0.128 ms
 2  bizXX.sta.linkcity.org.XX.22.72.in-addr.arpa (72.22.XX.XX)  0.412 ms  0.315 ms  0.312 ms
 3  10.200.100.1  6.961 ms  0.499 ms  0.474 ms
 4  sl-gw16-kc-3-1.sprintlink.net (160.81.151.109)  0.564 ms  0.437 ms  0.491 ms
 5  sl-crs1-kc-0-5-0-0.sprintlink.net (144.232.11.152)  1.073 ms  0.827 ms  0.737 ms
 6  sl-crs1-chi-0-1-0-3.sprintlink.net (144.232.18.214)  12.008 ms  12.409 ms  11.996 ms
 7  sl-st20-chi-13-0-0.sprintlink.net (144.232.20.3)  11.603 ms  11.579 ms  11.569 ms
 8  144.232.8.114  11.715 ms  11.777 ms  11.657 ms
 9  ae-32-52.ebr2.Chicago1.Level3.net (4.68.101.62)  12.476 ms  21.324 ms  18.234 ms
10  ae-5.ebr2.Chicago2.Level3.net (4.69.140.194)  12.354 ms  12.639 ms  12.676 ms
11  ae-2-2.ebr2.Washington1.Level3.net (4.69.132.70)  33.594 ms  33.414 ms  33.252 ms
12  ae-62-62.csw1.Washington1.Level3.net (4.69.134.146)  46.577 ms  39.840 ms  35.910 ms
13  ae-1-69.edge2.Washington4.Level3.net (4.68.17.19)  33.635 ms  33.585 ms  33.636 ms
14  xe-0-2-0.cr1.iad1.us.nlayer.net (4.79.168.74)  33.761 ms  33.292 ms  73.096 ms
15  vl74.ar1.iad1.us.nlayer.net (69.31.31.190)  33.976 ms  33.986 ms  34.315 ms
16  as6450.vl134.ar1.iad1.us.nlayer.net (69.31.31.115)  33.968 ms  33.436 ms  33.511 ms
17  dns5.docforge.org (198.186.193.20) [open]  33.906 ms  33.987 ms  34.153 ms
[10:39:25 root@allover:~]#


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Re: What Is Causing This Failure

Carlwill
On Tue, Dec 1, 2009 at 11:42 AM, Terry L. Inzauro
<[hidden email]> wrote:
>
> why all the off topic posts today?

I suspected this to be Postfix or Mail related so I posted here. It
was determined with the help of the list it was not a MTA issue.
Simple as that!

Sorry for any inconvenience.
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Re: What Is Causing This Failure

Stan Hoeppner
In reply to this post by Carlwill
Carlos Williams put forth on 12/1/2009 9:32 AM:

> I am unable to connect via Telnet so it appears to be a network / ISP issue.
>
> carlos@tunafish:~$ telnet 198.186.193.20 25
> Trying 198.186.193.20...
> telnet: Unable to connect to remote host: No route to host

Definitely a network problem between you and the remote host.  Works
fine here in the US:

greer:/etc/postfix# ping 198.186.193.20
PING 198.186.193.20 (198.186.193.20) 56(84) bytes of data.
64 bytes from 198.186.193.20: icmp_seq=1 ttl=51 time=79.1 ms
64 bytes from 198.186.193.20: icmp_seq=2 ttl=51 time=78.9 ms
64 bytes from 198.186.193.20: icmp_seq=3 ttl=51 time=78.7 ms
64 bytes from 198.186.193.20: icmp_seq=4 ttl=51 time=78.7 ms
^C
--- 198.186.193.20 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3012ms
rtt min/avg/max/mdev = 78.729/78.883/79.151/0.263 ms

greer:/etc/postfix# telnet 198.186.193.20 25
Trying 198.186.193.20...
Connected to 198.186.193.20.
Escape character is '^]'.
220 share.docforge.org ESMTP Postfix
quit
221 2.0.0 Bye

--
Stan
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Re: What Is Causing This Failure

Stan Hoeppner
In reply to this post by Carlwill
Carlos Williams put forth on 12/1/2009 10:05 AM:

> On Tue, Dec 1, 2009 at 10:43 AM, Ralf Hildebrandt
> <[hidden email]> wrote:
>> What is the output of traceroute 198.186.193.20 ?
>
> I get no results from my mail server:
>
> traceroute to 198.186.193.20 (198.186.193.20), 30 hops max, 40 byte packets
>  1  * * *
>  2  * * *
>  3  * * *
>  4  * * *
>  5  * * *
> .
> .
> .
> 29  * * *
> 30  * * *
>
> Strange...

Try:

traceroute -N 1 198.186.193.20

Debian 5.0.3 traceroute defaults to 16 simultaneous probes.  Other OSes
may bulk up as well.  I initially had the same problem as you.  Using -N
1 sends one probe at a time, and works for me:

greer:/etc/postfix# traceroute 198.186.193.20
traceroute to 198.186.193.20 (198.186.193.20), 30 hops max, 40 byte packets
 1  . (192.168.100.1)  0.880 ms  1.143 ms  1.388 ms
 2  mo-65-41-216-193.sta.embarqhsd.net (65.41.216.193)  36.706 ms
38.327 ms  40.772 ms
 3  mo-69-68-110-209.sta.embarqhsd.net (69.68.110.209)  42.654 ms
45.076 ms  47.070 ms
 4   (206.51.71.197)  80.981 ms  83.123 ms  84.785 ms
 5  bb-dllstx37-jx9-02-xe-11-1-0.core.centurytel.net (206.51.69.25)
87.971 ms * *
 6  * * *
 7  * * *
 8  * * *
 9  * * *
10  * * *
11  * * *
12  * * *
13  * * *
14  * * *
15  * * *
16  * * *
17  * * *
18  * * *
19  * * *
20  * * *
21  * * *
22  * * *
23  * * *
24  * * *
25  * * *
26  * * *
27  * * *
28  * * *
29  * * *
30  * * *

greer:/etc/postfix# traceroute -N 1 198.186.193.20
traceroute to 198.186.193.20 (198.186.193.20), 30 hops max, 40 byte packets
 1  . (192.168.100.1)  0.503 ms  0.502 ms  0.463 ms
 2  mo-65-41-216-193.sta.embarqhsd.net (65.41.216.193)  38.047 ms
35.821 ms  35.869 ms
 3  mo-69-68-110-209.sta.embarqhsd.net (69.68.110.209)  35.522 ms
35.837 ms  35.682 ms
 4   (206.51.71.197)  67.361 ms  66.997 ms  67.789 ms
 5  bb-dllstx37-jx9-02-xe-11-1-0.core.centurytel.net (206.51.69.25)
68.497 ms  68.432 ms  67.764 ms
 6  bb-dllstx37-jx9-01-ae0.core.centurytel.net (206.51.69.57)  67.016 ms
 66.762 ms  72.675 ms
 7  * * *
 8  po3-30g.ar1.dfw1.us.nlayer.net (69.31.63.154)  69.074 ms  69.489 ms
 69.022 ms
 9  te4-1.ar1.iah1.us.nlayer.net (69.22.142.113)  73.907 ms  73.942 ms
74.405 ms
10  xe-2-2-0.cr1.atl1.us.nlayer.net (69.22.142.118)  73.474 ms  73.845
ms  74.193 ms
11  xe-0-1-0.cr2.iad1.us.nlayer.net (69.22.142.106)  79.535 ms  80.066
ms  80.077 ms
12  vl72.ar1.iad1.us.nlayer.net (69.31.31.158)  79.094 ms  80.838 ms
79.838 ms
13  as6450.vl134.ar1.iad1.us.nlayer.net (69.31.31.115)  79.145 ms
81.074 ms  80.578 ms
14  dns5.docforge.org (198.186.193.20)  80.306 ms !X  80.124 ms !X
81.516 ms !X

man traceroute

-N squeries

Specifies  the  number of probe packets sent out simultaneously.
Sending several probes concurrently can speed up traceroute
considerably. The default value is 16.  Note that some routers and hosts
can use ICMP rate throttling. In such a situation specifying too large
number can lead to loss of some responses.

--
Stan