Question

Blacklisted IP

Asked by: Victor_Torres

Hi!
     I'm currently having this problem at our office.  For some reason our IP keeps getting blacklisted from spamcop and others sites alike.   Now our email does not reach it's destination nor bounce back to us, it just disappears.  Could this be a virus on our network?  Some suggest  blocking port 25 on each pc, if I do this will the user still be able to send and recieve email?  Why do I need to block port 25?
Please Help
thanks

This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.

Subscribe now for full access to Experts Exchange and get

Instant Access to this Solution

  • Plus...
  • 30 Day FREE access, no risk, no obligation
  • Collaborate with the world's top tech experts
  • Unlimited access to our exclusive solution database
  • Never be left without tech help again

Subscribe Now

Asked On
2009-08-24 at 05:37:00ID24676305
Topics

Network Software Firewalls

,

Spam Black Holes

,

TCP/IP

Participating Experts
6
Points
500
Comments
22

Trusted by hundreds of thousands everyday for fast, accurate and reliable tech support.

  • "The time we save is the biggest benefit of Experts Exchange to Warner Bros. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange." Mike Kapnisakis, Warner Bros.
  • "Our team likes having a resource that is more secure than just using Google and most experts using this service really know their stuff. It's nice to look here first versus using Google." Dayna Sellner, Lockheed Martin
  • "Anytime that I've been stumped with a problem, 9 out of 10 times Experts Exchange has either the accepted solution or an open discussion of the potential solution to the problem." Kenny Red, eBay Inc.

See what Experts Exchange can do for you.

Got a question?

We've got the answer.

Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.

Screenshot of Experts Exchange Knowledgebase

Need individual assistance?

Our experts are ready to help.

If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.

Screenshot of Experts Exchange Knowledgebase

Want to learn from the best?

Read articles from industry experts.

Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.

Screenshot of an Article

Working on a long term project?

Store your work and research.

Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.

Screenshot of Experts Exchange Knowledgebase

Access the answers to your technology questions today.

Subscribe Now

30-day free trial. Register in 60 seconds.

What Makes Experts Exchange Unique?

Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.

Trusted by the world's most respected brands.

image of each brand's logo

Faithfully serving IT professionals since 1996.

Experts Exchange Logo

Try it out and discover for yourself.

Subscribe Now

30-day free trial. Register in 60 seconds.

Related Solutions

  1. Blacklisted IP
    Hi, Have asked a couple of question today about email marketing and using foreign hosting solutions. So I am now happy :) but in the process of chatting with a hosting comapny in India, whose datacenter is in USA. They are completely paranoid about getting there server ...
  2. Blacklisting
    My corporate clients keep getting blacklisted and end up unable to send email for days or weeks at a time. A whole business not being able to send email is a huge problem as you can imagine. What devices and/or software can I implement to stop the blacklisting? My clients run...
  3. Public IP listed on Spam Mail Blacklist
    Our company network is setup to use NAT so that all the workstations only use one public IP. I'm not really sure how or why this IP has ended up on the Spam Mail Blacklist, but it has. Another company hosts our email accounts. Lets say its testdomain.com. Bob@testdomain.c...

Free Tech Articles

  1. WARNING: 5 Reasons why you should NEVER fix a computer for free.
    It is in our nature to love the puzzle. We are obsessed. The lot of us. We love puzzles. We love the challenge. We thrive on finding the answer. We hate disarray. It bothers us deep in our soul. W...
  2. SCCM OSD Basic troubleshooting
    SCCM 2007 OSD is a fantastic way to deploy operating systems, however, like most things SCCM issues can sometimes be difficult to resolve due to the sheer volume of logs to sift through and the dispe...
  3. Migrate Small Business Server 2003 to Exchange 2010 and Windows 2008 R2
    This guide is intended to provide step by step instructions on how to migrate from Small Business Server 2003 to Windows 2008 R2 with Exchange 2010. For this migration to work you will need the fo...
  4. Create a Win7 Gadget
    This article shows you how to create a simple "Gadget" -- a sort of mini-application supported by Windows 7 and Vista. Gadgets can be dropped anywhere on the desktop to provide instant information, ...
  5. Outlook continually prompting for username and password
    There have been a lot of questions recently regarding Outlook prompting for a username and password whilst using Exchange 2007. There are a few reasons why this would happen and I will try to cover t...
  6. Backup Exchange 2010 Information Store using Windows Backup
    There seems to be quite a lot of confusion around the ability to backup Exchange 2010 using the built in Windows Backup feature. This stems from the omission of this feature prior to Exchange 2007 s...

Cloud Class Webinars

  1. Avoiding Bugs in Microsoft Access
    Alison Balter takes and in-depth look at avoiding bugs in Access. In this webinar you will learn about using the immediate window to debug your applications, invoking the debugger, using breakpoints to troubleshoot, stepping through code, setting the next statement to execute, ...
  2. Top 10 Best New Features in Visio 2010
    Scott Helmers gives live demonstrations of the top 10 new features in Visio 2010. This webinar will teach you how to create compelling diagrams by adding shapes to the page with a single click, linking the shapes in a diagram to data in Excel (or SQL Server, or SharePoint), ...
  3. IT Consultant Business Secrets Revealed
    Michael Munger, Experts Exchange tech pro and IT consultant, pulls back the curtain on his very successful businesses and answers question on every IT consultant and business owner should know about. He shares secrets on what he did to solve the 5 most common problems in IT, ...
  4. Disaster Recovery and Business Continuity
    Quest CTO, Mike Billon, gives an overview of the steps involved in building a dunamic disaster recovery plan. Through case studies and an examination of software/hardware tooles for monitoring and testing, you'll gain a better understandin of where you are, where you want ...
  5. Organize Your Visio Diagrams with Containers and Lists
    Scott Helmers uses cross functional flowcharts, wireframe diagrams, data graphic legends and seating charts to teach you: how to ustilize all three new structured diagram components in Visio 2010, the best practices for organizeing shapes in previous version of Visio, how to organize ...
  6. How to Us Objects, Properties, Events and Methods in Microsoft Access
    Alison Dalter gives an in-depbth look at objects, properties, events and methods in Microsoft Access. In this webinar you will learn about using the object browser, referring to objects, working with properties and methods, working with object variables, understanding the ...

Join the Community

Give a Little. Get a Lot.

Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.

Join the Community

Answers

 

by: liddlerPosted on 2009-08-24 at 05:51:20ID: 25167747

port 25 (SMTP) is used by mailservers, a PC does not to have port 25, as it is a mail client (IMAP / POP).
The only machines in your network that should be allowed port 25 outbounds are your mailservers.
You should block all mail traffic, except for your mail server, at your perimeter (firewall, router gateway) rather than just each PC.

 

by: ks_adminPosted on 2009-08-24 at 06:45:57ID: 25168220

Liddler is correct, your firewall should only allow outbound TCP port 25 (SMTP) from the IP address of your mail server.  

However, I'm not sure from your post if you host your own email, (and if so if you're using Exchange or other) or if you have a third party hosting, etc.  But either way, you may want to do some packet level logging/inspection of your outbound traffic to get a clear picture of the SMTP traffic leaving your network.

Most firewall/routers will allow you to view/log outbound TCP port 25 and see what internal IP addresses are making outbound connections.  You could very well have an infected machine mass mailing junk, or it could be your email server is infected.  Also make completely sure that your email server is running up to date antivirus software, and that you've scanned and cleaned any infections on it.

 

by: vikingtechnologiesPosted on 2009-08-24 at 11:51:17ID: 25171198

Yes it's a virus mostly like a trojan.
You can't send mail because the ip of the mail server is blacklisted not the ip of you'r computer.If you browse with the same ip that the email server has it's bad.
The best thing to do is add another ip to the server. One for the user to browse the internet(nat) and one for the mail server. This is crucial. In this way even if the network is infected the ip of the mail server is not blacklisted.
Make a full sistem's scan and you will fine some malware for sure.

 

 

by: Victor_TorresPosted on 2009-08-24 at 16:54:45ID: 25173631

Thanks for the quick replies.  We are starting to manually scan each PC. Sad to say our firewall is still on backorder .  We are currently usiing 2003 server configured as NAT.  And we don't host our own mail server.   Does this mean that I can block port 25 on all pc including the NAT Server?

 

by: bmsjeffPosted on 2009-08-24 at 18:33:02ID: 25174004

You can use windows firewall to block port 25.
If you have a router, you can also block port 25 or redirect.

 

by: vikingtechnologiesPosted on 2009-08-24 at 23:01:51ID: 25174833

If the IP of the mail server is blacklisted it's no use to block smtp port 25 on you'r network.It is a problem on the ISP that hosts the mail server.

 

by: ollfriedPosted on 2009-08-24 at 23:36:35ID: 25174959

That would only be true if you don't host mails on your own.

Another point: Do NOT require delisting of your IP without solving the root problem! If you do, it will become harder to get off these lists.

 

by: Victor_TorresPosted on 2009-08-25 at 04:33:14ID: 25176358

I tried blocking port 25 but everytime I do I can't send/recieve email.  Where exactly on window XP firewall can I block port 25 and how?

Again Thanks

 

by: bmsjeffPosted on 2009-08-25 at 04:58:09ID: 25176520

Blocking port 25 should not effect receiving mail.  Are you sure that you are using you ISP to host your email, or do they just host your domain?  Go to http://www.mxtoolbox.com/ to see where your MX record is pointing.

http://support.microsoft.com/kb/813878 to block ports.  
How long till your firewall arrives?  May be worth while to get an alternative device.

 

by: Victor_TorresPosted on 2009-08-25 at 07:05:31ID: 25177705

Hi bmsjeff.
   I went to mxtoolbox and looked up our domain and it pointed to mail-incoming.gate.com and mail-incoming2.gate.com  I click on Diagnostic for both and mail-incoming2.gate.com resulted with  "Reverse DNS FAILED! This is a problem."  I clicked on black list and it states that IP is listed on spamcannibal.  Is this a problem with our ISP or our mail server provider gate.com?  
Again Thanks

Thanks

 

by: vikingtechnologiesPosted on 2009-08-25 at 07:10:16ID: 25177754

A good mail server has a reverse dns. Some mail server will drop you'r mail if you'r server does not have a reverse dns host.

 

by: ks_adminPosted on 2009-08-25 at 07:12:22ID: 25177775

Who controls your DNS?  If it is you, go in and add the proper reverse dns entries for your IP address.  If it's your ISP, have them do it immediately.

 

by: liddlerPosted on 2009-08-25 at 07:14:09ID: 25177798

Many mail gateways refuse to accept mail and you may be blacklisted if you do not have a PTR record (reverse DNS) for your mailserver, this should be done by the ISP that owns the IP address of your outbound mailserver
mail-incoming.gate.com (64.71.41.19)
there should be a PTR record 19.41.71.64.in-addr.arpa pointing back to the mailserver, this sohlud be donw by the owner of the IP block  64.71.0.0 to 64.71.63.255 which looks like HOSTWAY-1 in Chicago

 

by: Victor_TorresPosted on 2009-08-25 at 07:51:33ID: 25178189

This is getting interesting.  
KS Admin.
    When you say DNS, This is different from our internal Domain controller (active directory) right?   The DNS that your talking about is the DNS that handles our internet connection (ISP)  and not our internal Domain (active directory).  Am I understanding this correctly?

 

by: liddlerPosted on 2009-08-25 at 07:53:16ID: 25178212

Yes you are correct this is the DNS out on the internet (often via your ISP)

 

by: Victor_TorresPosted on 2009-08-25 at 08:10:06ID: 25178400

Hi Lidder.
    Is this something that the mailserver provider should be working on or the  ISP provider?  We called gate.com and they said thier side is fine.  We called our ISP and they are puzzled with our problem and suggested to use thier smtp.

 

by: ks_adminPosted on 2009-08-25 at 08:55:56ID: 25178921

Using their SMTP would certainly help, but I'm not sure we ever found out what type of email you have, Exchange, Qmail, etc...  or is it hosted?

If it's hosted, you would be better served to use your ISP's SMTP as a quick fix..

 

by: ks_adminPosted on 2009-08-25 at 08:56:59ID: 25178930

Also wanted to add that are you sure you've found out why you were blacklisted, and solved the original problem?

Have all your virus/malware scans come up clean?

 

by: Victor_TorresPosted on 2009-08-25 at 20:56:03ID: 25184323

hI ks admin,
     We mainly use MS Outlook and MS Exchange, they are both hosted by gate.com.  As of this moment we are going to individual computers and mannually scanning them for virus and spyware. What other action can I take to solve and prevent this from happening?
 

 

by: bmsjeffPosted on 2009-08-26 at 04:46:00ID: 25186477

Do you have an exchange server in house?

 

by: ks_adminPosted on 2009-08-26 at 06:22:35ID: 25187264

What IP address is actually blacklisted?

If you go to http://www.ipchicken.com , see what IP address it shows.  That is your public IP address...   if this IP address is the one blacklisted, then the problem would surely be on your internal network somewhere.

If it's another IP address that is blacklisted, then it probably belongs to gate.com, and they need to be figuring this out.

Hope that makes sense?

 

by: jdtinsPosted on 2009-08-27 at 13:33:38ID: 25202408

You can also check http://www.dnsstuff.com to veriffy DNS settings for the domain.

20120131-EE-VQP-002

3 Ways to Join

30-Day Free Trial

The Experts

98% positive feedback on 31,087 answers since March 2000. angeliii is a Microsoft Most Valuable Professional for his work with MS SQL Server & Develoment.

He has also proven his knowledge of Visual Basic Programming, PHP Scripting and Oracle Databases.

The Experts

97% positive feedback on 10,752 answers since July 2000. lrmoore has more than 18 years experience in the networking industry.

The six-time Mircosoft MVPs specialties include firewalls, virtual private networking, and network management.

Testimonials

"...and excellent source for support... Kind of like having your very own IT dept." Electriciansnet

Testimonials

"I was apprehensive at signing up at first. However... it has already made my life as an IT administrator much easier." JaCrews

Testimonials

"WOW! You guys have great, active, and knowledgeable people on here." moore50

Business Clients

Business Clients

In the Press

"If you’ve got a question... Experts Exchange can supply an answer.”

In the Press

"...an invaluable aid for both IT professionals and those who require tech support."

In the Press

"where IT professionals provide quick answers on just about any topic"

Business Account Plans

Loading Advertisement...