Re: [courier-users] DNS lookup problem

2016-05-12 Thread Sam Varshavchik

Bowie Bailey writes:


On 5/11/2016 7:45 PM, Sam Varshavchik wrote:
> Bowie Bailey writes:
>
>> $ testmxlookup westportyachtsales.com
>> Domain westportyachtsales.com:
>> Relay: mail.westportshipyard.com, Priority: 10, Address:
>> :::208.91.197.132
>
> There's something wrong with the westportshipyard.com domain.
...
> Looks to me like this domain's bill was due last month, and it was not
> paid, and the registrar took ownership of it.

Looks like you are right.  The westportshipyard.com website returns a
Network Solutions parking page.

However, that doesn't explain why testmxlookup and manual dns queries
return different results.  I ran a tcpdump on the mail server this
morning and found that testmxlookup is requesting an  record for
some reason.  When it doesn't get a result, it gives a soft error rather
than looking for the A record (which does exist).

[udp sum ok] 9540+ ? mail.westportshipyard.com. (43)
[udp sum ok] 9540 ServFail q: ? mail.westportshipyard.com. 0/0/0 (43)


Indeed. The parking NSes are broken, and throw up a SERVFAIL in response to  
a DNS query.



How do I prevent Courier from trying to use ipv6?


Only by recompiling Courier without any IPv6 support.

IPv6 has been here for a while. It's not a new kid on the block. If a DNS  
server barfs in response to an  query, it's the DNS server's problem.




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Re: [courier-users] DNS lookup problem

2016-05-12 Thread Bowie Bailey
On 5/11/2016 7:45 PM, Sam Varshavchik wrote:
> Bowie Bailey writes:
>
>> $ testmxlookup westportyachtsales.com
>> Domain westportyachtsales.com:
>> Relay: mail.westportshipyard.com, Priority: 10, Address:
>> :::208.91.197.132
>
> There's something wrong with the westportshipyard.com domain.
...
> Looks to me like this domain's bill was due last month, and it was not 
> paid, and the registrar took ownership of it.

Looks like you are right.  The westportshipyard.com website returns a 
Network Solutions parking page.

However, that doesn't explain why testmxlookup and manual dns queries 
return different results.  I ran a tcpdump on the mail server this 
morning and found that testmxlookup is requesting an  record for 
some reason.  When it doesn't get a result, it gives a soft error rather 
than looking for the A record (which does exist).

[udp sum ok] 9540+ ? mail.westportshipyard.com. (43)
[udp sum ok] 9540 ServFail q: ? mail.westportshipyard.com. 0/0/0 (43)

How do I prevent Courier from trying to use ipv6?

-- 
Bowie

--
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Re: [courier-users] DNS lookup problem

2016-05-11 Thread Sam Varshavchik

Bowie Bailey writes:


$ testmxlookup westportyachtsales.com
Domain westportyachtsales.com:
Relay: mail.westportshipyard.com, Priority: 10, Address:
:::208.91.197.132


There's something wrong with the westportshipyard.com domain.

Its registrar is network solutions.

$ whois westportshipyard.com.
[Querying whois.internic.net]
[Redirected to whois.networksolutions.com]
[Querying whois.networksolutions.com]
[whois.networksolutions.com]


No match for "WESTPORTSHIPYARD.COM.".

And poking whois.internic.net without redirection:

  Domain Name: WESTPORTSHIPYARD.COM
  Registrar: NETWORK SOLUTIONS, LLC.
  Sponsoring Registrar IANA ID: 2
  Whois Server: whois.networksolutions.com
  Referral URL: http://networksolutions.com
  Name Server: NS1.PENDINGRENEWALDELETION.COM
  Name Server: NS2.PENDINGRENEWALDELETION.COM
  Status: clientTransferProhibited  
https://icann.org/epp#clientTransferProhibited

  Updated Date: 24-apr-2016
  Creation Date: 21-apr-1996
  Expiration Date: 22-apr-2017

This domain's name servers look suspicious.

Looks to me like this domain's bill was due last month, and it was not paid,  
and the registrar took ownership of it.





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Re: [courier-users] DNS lookup problem

2016-05-11 Thread Bowie Bailey
On 5/11/2016 4:11 PM, Gordon Messmer wrote:
> On 05/11/2016 12:31 PM, Bowie Bailey wrote:
>> $ testmxlookup westportyachtsales.com
>> westportyachtsales.com: soft error.
>
> Have you checked for errors in your DNS server's logs?

No errors that I can see.

I guess I could use tcpdump to see what is actually happening.

-- 
Bowie

--
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Re: [courier-users] DNS lookup problem

2016-05-11 Thread Gordon Messmer
On 05/11/2016 12:31 PM, Bowie Bailey wrote:
> $ testmxlookup westportyachtsales.com
> westportyachtsales.com: soft error.


Have you checked for errors in your DNS server's logs?


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[courier-users] DNS lookup problem

2016-05-11 Thread Bowie Bailey
I have an outgoing email sitting in my mail queue due to a DNS failure, 
but I can't figure out why it is failing.  When I test it manually, this 
is what I see:

$ testmxlookup westportyachtsales.com
westportyachtsales.com: soft error.

$ dig @172.16.17.201 westportyachtsales.com mx +short
10 mail.westportshipyard.com.

$ dig @172.16.17.201 mail.westportshipyard.com +short
208.91.197.132

$ testmxlookup westportyachtsales.com
Domain westportyachtsales.com:
Relay: mail.westportshipyard.com, Priority: 10, Address: 
:::208.91.197.132

172.16.17.201 is the first DNS server listed in resolv.conf, which is 
what Courier and testmxlookup should be using if I understand 
correctly.  It also works if I query the second DNS sever manually. Now 
that I've gotten a response, testmxlookup will work for a while, but 
eventually it will start giving the soft error again for that domain.  I 
am guessing that this is due to my DNS server caching the result, but 
why would my manual queries succeed and testmxlookup fail the first 
time?  The queries are both coming from the same user on the same machine.

-- 
Bowie

--
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bring their own devices (BYOD) to work are irked by the imposition of MDM
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apps on BYO-devices by containerizing them, leaving personal data untouched!
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