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Ellen098

join:2003-05-04
united state
reply to NormanS

Re: can't change supposedly dynamic IP address

I'm glad you mentioned that. I checked the notice again & was surprised by what I saw. I've replaced the actual email address, my IP address, & another IP address below:

Reporting-MTA: dns; dsmdc-mail-omta-03 [10.4.20.34]
Received-From-MTA: dns; [127.0.0.1] [my IP address]
Arrival-Date: Tue, 16 Oct 2012 13:59:04 -0500

Final-recipient: rfc822; [email address]
Action: failed
Status: 5.1.1
Diagnostic-Code: smtp; 550 Unable to add [email address] because host=
[different IP address] is listed on RBL bl.spamcop.net
Last-attempt-Date: Tue, 16 Oct 2012 13:59:05 -0500
So, it appears that it's not my IP address on Spamcop's blacklist but the "different IP address" which, according to arin.net, belongs to "MEDIACOM-ENTERPRISE-CUST". If the business that I've been having this problem with is a Mediacom customer, does this mean that it's their IP which has been blocked from receiving emails? If not, do you have any suggestions?

Thanks very much!


NormanS
I gave her time to steal my mind away
Premium,MVM
join:2001-02-14
San Jose, CA
kudos:11
Reviews:
·SONIC.NET
·Pacific Bell - SBC

1 edit

Is your "Final-recipient" email address for another Mediacom user?

Interesting. Looking up the MX record for 'mchsi.com' gives me a host name. When I attempt to connect, I get:

C:\Dig>telnet smtp.mchsi.com 25
Connecting To smtp.mchsi.com...
220 dsmdc-mail-imta-02 bizsmtp ESMTP server ready
quit
221 2.0.0 dsmdc-mail-imta-02 bizsmtp closing connection
 
Connection to host lost.
 
Compare the host name in my test: "dsmdc-mail-imta-02" ...
... with the "Reporting-MTA" host namefrom your DFN: "dsmdc-mail-omta-03".

"Omta"="Outbound Mail Transfer Agent"?
"Imta"="Inbound Mail Transfer Agent"?

My SWAG is that 'smtp.mchsi.com' ('dsmdc-mail-imta-02') is blocking 'mail.mchsi.com' ('dsmdc-mail-omta-03'). IOW, Mediacom is blocking themselves due to a Spamcop.net RBL listing. Administrative incompetence?

--
Norman
~Oh Lord, why have you come
~To Konnyu, with the Lion and the Drum

Ellen098

join:2003-05-04
united state

Very interesting. If that's true, I wonder if lots of other people are running into this problem too. I'll try smtp.mchsi.com next to see if that helps. Hopefully a server won't block itself. If it doesn't help, I'll try mediacombb.net, which I had to use for awhile last year after an "upgrade". Do you know if mediacombb.net uses the same IP as mchsi.com?

Also, the final user is not a Mediacom subscriber.

BTW, how do you find out an MX record? Thanks very much for checking this out.



NormanS
I gave her time to steal my mind away
Premium,MVM
join:2001-02-14
San Jose, CA
kudos:11
Reviews:
·SONIC.NET
·Pacific Bell - SBC

said by Ellen098:

I'll try smtp.mchsi.com next to see if that helps.

But 'smtp.mchsi.com' is not a message submission server, and it obviously uses DNSBLs to control spam. If your residential IP Address is in any DNSBL used by 'smtp.mchsi.com', the connection will be terminated with prejudice.

Why aren't you using the message submission server designated on the official Mediacom web site?

»mediacomcable.com/CustomerSuppor···ail.html

BTW, how do you find out an MX record?

A command line utility which comes with the Windows port of the Linux DNS server, "Bind".
C:\Dig>dig mx mchsi.com
 
; <<>> DiG 9.9.1-P2 <<>> mx mchsi.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 41976
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1
 
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;mchsi.com.                     IN      MX
 
;; ANSWER SECTION:
mchsi.com.              3600    IN      MX      10 smtp.mchsi.com.
 
;; AUTHORITY SECTION:
mchsi.com.              106089  IN      NS      ns1.mcomdc.com.
mchsi.com.              106089  IN      NS      ns2.mcomdc.com.
 
;; Query time: 150 msec
;; SERVER: 192.168.42.1#53(192.168.42.1)
;; WHEN: Fri Oct 19 17:42:28 2012
;; MSG SIZE  rcvd: 102
 

--
Norman
~Oh Lord, why have you come
~To Konnyu, with the Lion and the Drum

Ellen098

join:2003-05-04
united state

I used the servers designated on the official site, mail.mediacombb.net, before I had to reinstall my email program early this year. I don't recall why I then set up the servers as mail.mchsi.com which is what they used to be before the "upgrade" a year or so ago. I've now changed them back to mail.mediacombb.net

I ran "Dig mx" from Terminal in my Mac for mchsi.com & mediacombb.net. The printouts didn't have an Authority section like yours did, but the Answer section showed smtp.mchsi.com or smtp.mediacombb.net, depending on which server I had requested information for. What's interesting though is that the IP addresses for the servers were the same, although they were different form what you got:

SERVER: 208.67.222.222#53(208.67.222.222)

Since the IP addresses are the same, I assume that means that my changing the outgoing server name shouldn't make a difference. Also, it's surprising that the IP you got for mchsi.com was completely different from from the one I got. Don't mail servers have static IPs?

Thanks for your answers.



NormanS
I gave her time to steal my mind away
Premium,MVM
join:2001-02-14
San Jose, CA
kudos:11
Reviews:
·SONIC.NET
·Pacific Bell - SBC

1 edit

said by Ellen098:

What's interesting though is that the IP addresses for the servers were the same, although they were different form what you got:

SERVER: 208.67.222.222#53(208.67.222.222)

Since the IP addresses are the same, I assume that means that my changing the outgoing server name shouldn't make a difference. Also, it's surprising that the IP you got for mchsi.com was completely different from from the one I got. Don't mail servers have static IPs?

I was puzzled by this comment. 208.67.222.222 is not even an mchsi IP address, much less a mail server address. The IP address in my printout is an RFC 1918 reserved IP address for private networks; it is my residential gateway (a Pace 4111N ADSL2+ modem with a router section). The IP address in your printout is the primary DNS server for OpenDNS. These are the respective DNS servers queried by our 'dig' commands!

The 'nslookup' command tells me that the servers are different:
C:\Dig>nslookup mail.mchsi.com
Server:  homeportal
Address:  192.168.42.1
 
Non-authoritative answer:
Name:    mail.mchsi.com
Address:  97.64.187.44
 
And then:
C:\Dig>nslookup mail.mediacombb.net
Server:  homeportal
Address:  192.168.42.1
 
Non-authoritative answer:
Name:    mail.mediacombb.net
Address:  97.64.187.40
 
BTW, the semi-colons are comment delimiters.

The "Question" section in my results recapitulates the question: "What is the name of the MX server for the 'mchsi.com' domain?"

The "Answer" section displays that server name.

The "Authority" section displays the authoritative name servers for the 'mchsi.com' domain.

The commented servers at the end are the recursive name servers used by the 'dig' command.

--
Norman
~Oh Lord, why have you come
~To Konnyu, with the Lion and the Drum

Ellen098

join:2003-05-04
united state

Thanks for your explanations. NSLookup found 97.64.187.40 & 97.64.187.44 as the IP addresses for mediacombb.net & mchsi.com, which is very close to the IP addresses which keep getting blocked - 97.64.187.22 & 97.64.187.24. In any case, I'm now using Mediacombb.net for my outgoing server & not surprisingly, the failed message errors are unfortunately continuing.