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Cablevision email problem when sending from inside Cablevision Optonline

Posted on 2016-11-01
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Last Modified: 2016-11-02
a friend has cablevision optonline home internet service with dynamic DHCP.

She's been using Windows Live Mail on her windows 7 machine to access her optonline (OOL) and gmail email accounts.

About a month ago, she wasn't able to send mail with Windows Live app using the optonline account: the OOL server wouldn't accept the mail.  And when she sent from gmail to OOL users via live mail app, it was blocked by Cablevision.

When using the gmail and OOL webmail, everything worked perfect. Calling OOL tech support they said one of her machines was infected with malware and they blocked her outbound sending ability.

we had checked her machine and told them it was clean. OOL then removed the block they said.

The problem came back recently.  She had a number for OOL shared services which is a 2nd tier part of support it seems.  But they were no help, blaming winfdows live app for the problem.  We installed thunderbird with the same results.  It would appear that her IP address was on RBLs which is what we saw. But OOL said they don't use the RBLs that we saw she was on.

I had her turn off her cable modem last night and this morning when powering it on, she got a different IP address.  But that one is on several RBLs also.

Then I started checking other IPs in those ranges and those are also on RBLs

would anyone have any advice? Are OOL IP address ranges automatically on some RBLs?  I can't see why or when these IP addresses were put on the RBLs.

or someone in the area gets the IP address, spams people till they get on RBLs, then gets another IP and repeat process?

She's considering moving to Fios to get a clean IP address?  But we have FIOS and just checked our IP address - we are on dnsbl and dun.dnsbl SORBS and  zen, PBL SPAMHAUS RBLs - the same ones that she's on.  Are those just lists of DDHCP pools?

Should she get a static IP?  She's just a home user.
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by:
Dr. Klahn earned 500 total points
ID: 41868375
Yes, some addresses are permanently blacklisted on the RBLs.  In particular, ISPs that host notorious or persistent spammers can get entire CIDR blocks banned.  There's also, as you have mentioned, the possibility that the cable modem took over an IP address that was previously used for spamming.  This happens more and more frequently as hosting companies decide that they can't afford to have their IP blocks perma-banned, and force spammers to infect individual end-user computers.

FWIW, I used to get a fair amount of spam on my own system from OOL IP blocks and for some time I blocked several of their IP ranges.

What can be done:  Incoming email will not be a problem, it's the outgoing that's the issue.  Sign up with an outgoing email relaying service such as SMTP2GO, which will relay email out reliably no matter what IP address the computer is sitting on.

Caveat:  Since relay services are in the business of relaying email and they can't afford to have their addresses blacklisted, be sure that the system is protected by antivirus, and run Malwarebytes and Spybot - S&D on it regularly.  Anything going through a relayer that sniffs of spam will get that account revoked PDQ.
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Author Comment

by:BeGentleWithMe-INeedHelp
ID: 41870475
Thanks for that info.  I've heard of relay services but never used them...  Changing the IP address at their house seems to have allowed optonline to accept mail coming from Gmail sent from her house and the optonline server allows her to send out through their server.  So problem solved for now...

The SMTP2Go service brings up another question...  I created (a free!  nice!) account.  I put in the credentials for the outbound server on one of my gmail accounts in outlook. I then sent an email from that account in outlook to one of my accounts that has spam filtering from Reflexion.  Usually reflexion adds a footer the 'real' email address it came from.   (when a company does a mailing and the from line says 'info@company.com', the 'real' address is something like this:

m-3iija1725hazfhllq3ufp284hsxukygajwlih0lazu9zhagpvhfnc@bounce.linkedin.com

I was expecting that footer to show some ___@smtp2go.com address.  Or the login info I used to log into the SMTP2go smtp server (not the same as that gmail account).

But the footer showed it came from my gmail account.  Kinda spoofing the email address it came from.  That sound right?   I thought with the spam filter at least, I wouldn't be able to spoof.

In the settings for this gmail account in outlook, I changed the email field from ____@gmail.com to gibberish@nonsense.com (that's exactly what I typed).  And I got an email THROUGH THE SPAM FILTER saying that gibberish@nonsense.com email address...  So with the single login info from smtp2go, put that in several different email accounts in outlook and they will all show the correct email address in the from field!?
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LVL 28

Expert Comment

by:Dr. Klahn
ID: 41870649
The SMTP2Go system is just a relayer, not an originator, so it will always show the originating domain and email address.
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Author Comment

by:BeGentleWithMe-INeedHelp
ID: 41870751
relayer / not originator... right.  But I'm able to spoof totally bogus email addresses going through them. Just wouldn't think I could do that.
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