Blacklist Knowledgebase

Empowering You, On Demand.

At Impressionwise, we maintain one of the industry's most comprehensive and actively monitored email blacklist knowledgebases, encompassing over 230 major RBL (Real-time Blackhole Lists) and URIBL (Uniform Resource Identifier Blacklists) sources. This extensive coverage allows us to detect and assess blacklist threats in real time, helping organizations protect their sender reputation, ensure maximum deliverability, and proactively mitigate risks before they impact campaign performance or inbox placement.

To learn more about what an email blacklist is and how it applies to your email delivery, see Understanding Blacklists.

Alternatively, you can search for a specific blacklist name.

Stop wondering and start knowing - Sometimes it’s easier to just ask. Please feel free to reach out to us with any questions to experience for yourself what sets Impressionwise apart!

Understanding Email Blacklisting

Blacklisting is a term that applies to the practice of identifying spammers based on the IP’s and domains that they send email from, then compiling this information into a list that can be referenced by email servers, which then blocks email from those IP’s being delivered to the intended recipient. This is an essential part of maintaining email as an effective tool, however based on the fact that blacklists operate on a largely independent and automated basis, they often mistake good senders for bad.

There are many specific reasons a blacklist may mistake a good sender for spam, but simply put, senders do not pay enough attention to their email marketing approach. If the only focus is to send email campaigns without understanding possible undesired effects, you’re potentially unintentionally triggering red flags and causing delivery issues. When properly managed, this risk can be entirely mitigated. This guide will get you on the right track when it comes to understanding the main concepts at play, and beginning to correct any bad email sending practice you currently have.

Email blacklists explained

1.	You send an email from readme@your-domain.com to John Doe and your IP address is x.x.x.x;
2.	John’s mail server takes your mail server’s IP address, resolves that into a domain name, and programmatically checks both the domain and IP against a collection of blacklist algorithms.
3.	If the IP address x.x.x.x (or the domain your domain.com) is blacklisted, your email is most likely landing in John’s junk mail folder, without its content being scanned. And if your IP or domain is flagged as a serial offender, ISPs will reject your emails automatically, meaning it won’t even reach John’s junk mail folder.

As you can see, there is a lot that goes in to determining your emails inbox status. Even if you do strictly follow email marketing best practices, you are at risk of being blacklisted inadvertently. Blacklists can frequently mistake legitimate senders as spammers due to their email sending habits.

Common blacklisting triggers

• Usually, legitimate senders will build their email lists over time and email volumes will increase gradually. A sudden surge in email sending volume indicates possible spammer behavior.
• Spammers are some of the world’s most active email senders. If sending very high volumes of email, the potential to be spotted on the spam monitoring radar increases as the general recipients responses increase.
• High spam complaint rates. Everyone involved in email marketing will receive the odd complaint –e.g. recipients may not recall opting in to receive your messages – however if the number of complaints are above the accepted threshold, ISPs may start routing your emails to spam folders or blocking your emails entirely.
• Poor email list hygiene can also land you on email blacklists. Sending messages to dormant or inactive email addresses that have been turned into recycled spam traps, or worse, harvested addresses that are actually pure spam traps, is detrimental to your sender reputation.
• Bad content. Certain words or phrases express spam-like content such as “free”or “Money back offer guaranteed”, as well as lots of red color in the body text, CAPS LOCK, lots of exclamation marks!!!!! etc. are all things that should be avoided.

Doing everything right and still on a blacklist?

Even though you may be following best email practices to a tee, it does happen. The good news is that you can perform email reputation management by monitoring the blacklists on the web. Your ISP should be doing this on your behalf, however, if you’re keen to check this out yourself, you can go to http://multirbl.valli.org/ – a basic tool to monitor whether you are blacklisted. Simply type in your domain or IP and this free multiple DNS Blacklist service will cross reference other blacklists by IPV4, IPV6, or domain.

If you are blacklisted, but believe you shouldn't be, or you’ve addressed the reasons that got you on to the list in the first place, you’ll need to take action to get your IP removed from the list. You can do this by applying for a “delisting” from the blacklist in question by contacting the blacklists’owner via their website.

The key is to be proactive and address these issues quickly to prove to the ISPs that you’re serious about your reputation and about remedying your delivery challenges.

Blacklist delisting guidelines

• If you are a serial offender, you will find delisting becomes increasingly difficult, if not impossible.
• Don’t attempt to argue with or get information from listing services. Rather focus on the facts and the remedies you put in place.
• Applying for delisting when you haven’t fixed the cause, e.g. receiving too many spam complaints, is a bad idea. Fix first and apply later.

Now that you know more about email blacklisting, you’ll agree that basic email reputation management is one you don’t want to neglect. Don’t assume your ESP will always monitor this for you, your ESP cannot stop ISPs from receiving negative responses from your recipients in your database.

It is up to you to maintain your brands reputation, and developing an effective marketing strategy on a foundation of email marketing best practices will prevent you getting blacklisted in the future.

ISP Information

Impressionwise maintains these ISP reference tables for the benefit of senders and systems administrators working to improve email delivery. The “Sender Support” table below offers a quick reference to various ISP postmaster pages, FBL pages and unblocking pages. The second table, “Delivery and Filtering Details”, lists known connect limits, spam filters and certification services.

Sender Support

ISP	Postmaster site	Feedback Loop	Whitelist	Support
AOL	Postmaster Website	FBL signup	Whitelist Signup	AOL support pages AOL Postmaster Blog
AT&T	Postmaster pages	does not offer	does not offer	SMTP errors list Blocklist removal form
Bellsouth (AT&T)		does not offer	does not offer
Charter	Postmaster pages	does not offer	does not offer
Comcast	Postmaster pages	FBL Signup	does not offer	Blocklist removal form
Cox	Postmaster pages	FBL Signup	does not offer	Blocklist removal form
Earthlink	Postmaster pages	Send email to fblrequest@abuse.earthlink.net	does not offer	Blocked users
Excite	Postmaster pages	FBL Signup	does not offer	does not offer
Fastmail		FBL Signup
GMX	mail.com
Gmail	Bulk senders guidelines	FBL FBL Signup for ESPs	does not offer	Troubleshooting
Hotmail (Outlook)	Hotmail
Integra	does not offer	does not offer	does not offer	does not offer
Juno	United Online
Live.com (Outlook)	Hotmail
Mail.com	Postmaster page	does not offer	does not offer	Contact Form
Mail.ru	Postmaster.mail.ru	FBL Signup
Netzero	United Online
Office365	Technet
OpenSRS	Tucows
Outlook	Postmaster Website	JMRPP Signup	does not offer	Outlook support pages
QQ	Postmaster Website	does not offer		does not offer
Rackspace	emailsrvr.com	FBL Signup	does not offer	postmaster@emailsrvr.com
Roadrunner	Postmaster pages	FBL Signup	does not offer	Support Request Page
Synacor		FBL Signup
Telenor		FBL Signup
Terra.com.br		FBL Signup
Time Warner Cable	RoadRunner
Tucows	does not offer	FBL Signup	does not offer	does not offer
United Online	Postmaster pages	does not offer	Whitelist Signup	Unblocking Form
Usa.net	Postmaster pages	FBL Signup	does not offer	IP lookup form
Verizon		does not offer	Whitelist Signup	does not offer
Yahoo	Postmaster Pages	FBL Signup	Yahoo! Mail Bulk Sender Form	Detailed Delivery Advice Postmaster Help
XS4ALL		FBL Signup
Zoho		FBL Signup

Delivery and Filtering Details

A little more information about the specifics of delivery at various ISPs. Note that the “does not publish” for limits means that the ISP has said they have limits, but they do not publish those limits specifically. Many of these ISPs tie sending limits to reputation; IPs with poor reputations have much lower sending limits than IPs with good reputations.

ISP	Connection	Sending Limits	Certification	Reputation Providers
AOL		500 emails per connection 100 recipients per message	Return Path Certified
AT&T	no published limits	no published limits	Return Path Certified
Bellsouth	no published limits	no published limits
Charter	no published limits	no published limits		no confirmed
Comcast	25 connections per IP address	100 recipients per message	Return Path Certified	Spamhaus Spamhaus ZEN Cloudmark CSI Return Path Reputation Network Blacklist.
Cox	5 connections per IP address	100 messages per connection	Return Path Certified	Spamhaus Zen Return Path DNSBL Invaluement SIP list Cloudmark CSI SURBL Spamhaus DBL Invaluement URI list
Earthlink	does not publish	does not publish	no known certification services
Excite	10 per IP	10 per connection	Return Path Certified	Cloudmark CSI blocklist Spamcop blocking list Return Path Senderscore blacklist internal
Fastmail				Spamhaus XBL Spamassassin
GMX
Gmail	does not publish		not using any
Hotmail (Outlook)	based on the reputation	based on the reputation	Return Path Certified
Integra	no published limits	100 emails per address
Juno
Live.com
Mail.com	very little information available	very little information available		has not published
Mail.ru
Netzero
OpenSRS
Outlook	500 simultaneous connections
QQ	1 connection per IP	1 email per connection
Rackspace	very little information available	very little information available	Return Path Certified	has not published
Roadrunner	do not publish	do not publish	Return Path Certified	Spamhaus ZEN Return Path Reputation Network Blacklist
Synacor
Terra.com.br
Time Warner Cable
Tucows	very little information available	very little information available	Return Path Certified	has not published
United Online
Usa.net	does not publish	does not publish	Return Path Certified	Cloudmark
Verizon			Return Path Certified	not known to use
Yahoo		20 emails per connection reputation based rate limiting	Return Path Certified	Spamhaus XBL Spamhaus PBL
Zoho

Threats API Overview

Our Hygiene API can be seamlessly integrated into your signup or onboarding process with just a single request. This high speed processing option is designed for continuous, real-time, data cleansing for cleansing an individual email address using standard HTTP methods.

Structure and Definition for Inbound Submissions

Our API requires you to authenticate each individual request. Below is an example of a basic URL structure request, just substitute with the provided account, associated password along with any optional parameters.

Structure: https://post.impressionwise.com/fastfeed.aspx?CODE=000001&PWD=password1&<paramlist>

Required Data Fields

Parameters need to be separated by "&"

&CODE= 6 Digit Alpha-numeric, account code provided by Impressionwise = 000001
&PWD= Alpha-numeric, security code provided by Impressionwise = password1
&EMAIL= Recipient email address to be submitted for processing = noexist@testme.com

Optional System Fields

&MX= To receive the MX domain information for an email address = 1

Optional Client Pass-thru Fields

&MX= To receive the MX domain information for an email address = 1

Optional Client Pass-thru Fields

Parameter's need to be separate by "&" = param1=value1&param2=value2&...

&fname=test
&lname=me
&addr1=123 sw 150 ave
&addr2=
&city=miami
&state=FL
&zip=33222
&country=USA
&phone=3057645678
&gender=m
&optinsite=www.impressionwise.com
&optindate=2010-02-10
&optinip=34.44.55.32
&other1=
&other2=

** Maximum of 20 "other" variables.

URL Structure Example

A properly formatted URL post would resemble the following example as shown below.

https://post.impressionwise.com/fastfeed.aspx?code=000001&pwd=askme&email=testme@impressionwise.com&fname=test&lname=me&addr1=123 sw 150 ave &addr2=&city=miami&state=FL&zip=33222&country=USA&phone=3057645678&gender=m&optinsite=www.impressionwise.com&optindate=2010-02-10&optinip=34.44.55.32

Parameters and Usage

To verify an email address simply use the request shown in the sample below substituting the required parameters with provided credentials and email address you want to verify.

Sample = https://post.impressionwise.com/fastfeed.aspx?code=000001&pwd=password1&email=noexist@testme.com

Upon successful posting of an email address, you can expect to receive the following response.

Response = EMAIL=noexist@testmelink.com&RESULT=INVALID&TTP=2.41

Possible result parameter/values include:

&RESULT= "See below section Result Code section for additional detail"
&TTP= "Time it took to process value represented in seconds"
&NPD= "See below section Net Protect Detail section for additional detail"
&CC= "See below section Country Code Detail section for additional detail"
&MXROOT= "MX domain name as per posted DNS"

Error Handling

From time to time you may experience an API error. It is important to watch out for these and handle them appropriately. Specifically, if your submission contains an invalid account code or password the result response would be WRONG_PSW.

Additionally, it has been our experience that with some smaller email hosts it is not uncommon for their reply to take an excessive amount of time to respond (sometimes more than 10 seconds). Due to this possible condition, you will receive a result code of RETRY. Upon reception of this response, please continue your HTTP submissions thru to completion of the entire data set to be submitted.. Once complete, please retry any/all responses with "RETRY" or as shown below:

Response = EMAIL=noexist@testmelink.com&RESULT=RETRY&TTP=1.33

If you receive any other response other than those previously shown, please contact support.

Result Codes

The recommended guidelines presented below will ensure you are adhering to email best practices, enabling more emails to reach the inbox. As a result, you will mitigate any risk associated with emailing to potentially "bad" addresses and you will experience additional opens, higher click through rates, increased conversions, and more revenue while protecting your online reputation.

The recommended guidelines presented below will ensure you are adhering to email best practices, enabling more emails to reach the inbox. As a result, you will mitigate any risk associated with emailing to potentially "bad" addresses and you will experience additional opens, higher click through rates, increased conversions, and more revenue while protecting your online reputation.

General Disclaimer: Every reasonable effort is made to locate all known threat and delivery classification elements mentioned herein, yet due to the constantly changing and dynamic nature of the online environment, we can not guarantee the results or deliverable will be free of any/all traps, threat or delivery classification elements identified within this report.

While every attempt has been made to ensure that the information in this document is accurate and complete, some typographical errors or technical inaccuracies may exist. Impressionwise does not accept responsibility for any kind of loss resulting from the use of information provided.

Questions? Please feel free to contact us with any questions or specific customization requirements you may have regarding our automated, data cleansing feed services to ensure a successful evaluation or use of our services and let the results speak for themselves!

Service Credits Balance API Overview

The Service Credits Balance API provides a seamless way to check the current balance of your account’s service credits. This API allows users to retrieve their available service credits through a simple, automated process, making it easier to manage and track usage. In this overview, we will guide you through how to access and use the API, including instructions on authentication, endpoint details, and the parameters required to successfully check your service credits balance. By following these steps, you'll be able to integrate the API into your system for real-time updates on your account's service credits.

Structure and Definition for Inbound Submissions

Our API requires you to authenticate each individual request. Below is an example of a basic URL structure request, just substitute with the provided account, associated password along with any optional parameters.

Structure: https://post.impressionwise.com/creditscheck.aspx?CODE=BBF&PSW=password

Required Data Fields

Parameters need to be separated by "&"

&CODE= 3 Digit Alpha-numeric, acccount code provided by Impressionwise = BBF. This code can be found in the Client Portal within the API Access section.
&PSW= Alpha-numeric, account password provided by Impressionwise = password. Same as Portal login password. If you are receiving WRONG_CREDENTIALS and if your password contains this character "&", then use "%26" as a replacement and re-attempt or contact us to assist.

Parameters and Usage

To retrieve the current service credits balance, simply use the request shown in the sample below substituting the required parameters with provided credentials and email address you want to verify.

Sample = https://post.impressionwise.com/creditscheck.aspx?code=BBF&psw=password

Upon successful posting, you can expect to receive the following response.

Response = CODE=BBF&CREDITS=136,012&TTP=0.41

Possible result parameter/values include:

&CODE= "3 Alpha-numeric, account code assigned by Impressionwise = BBF”. This code can be found in the Client Portal within the API Access section.
&CREDITS= "Numeric value representing the accounts, current service credits balance"
&TTP= "Time it took to process value represented in seconds"

Error Handling

From time to time you may experience an API error. It is important to watch out for these and handle them appropriately. Specifically, if your submission contains an invalid account code or password the result response would be WRONG_CREDENTIALS.

If you receive any other response other than those previously shown, please contact support.

Questions? Please feel free to contact us with any questions or specific customization requirements you may have regarding our automated, data cleansing feed services to ensure a successful evaluation or use of our services and let the results speak for themselves!

Bulk FTP Transfer

Designed for automated, batched submissions of larger volume data sets. This service is designed for those clients who receive data on a regularly scheduled basis with 24/7 access to Impressionwise cleaning services without the wait time of traditional processing in a secure manner. Provided below is the site information required to access via FTP.

URL:		ftp://feed.impressionwise.com
FTP Mode:		Passive Mode
Username:		FTPDataXXX (case sensitive) (Provided in email from IW sales Rep.)
Password:		XXXXXXXXX (case sensitive) (Provided in email from IW sales Rep.)

Place files within the \ToBeCleaned\ folder to begin cleansing process and results will be placed with a folder named \Cleaned\.

Note: Only attempt to only upload delimited (tab, pipe or comma) files with extensions like txt, csv, xls, xlsx, zip, or rar. All other file extensions not listed will not be processed. You may upload a file containing as many fields of information as you wish, yet we require, at a minimum, the email address when scanning the files.

Questions? Please feel free to reach out with any questions you may have about our cleansing process or your results, and we look forward to you experiencing the results that truly set Impressionwise apart!

Bulk API List Submission

Sending a file by URL

The URL submitted must lead directly to the file and contain the type of input used, as well as any authentication credentials the request needs. The URL should be sent in the request as the input parameter and the input_type should be set to url. Below is an example request:

Sending data directly

Data submitted directly should exist as an array of arrays or an array of objects. The data should be sent in the request as the input parameter and the input_type should be set to data. Below is an example of this request:

Request Response

When you submit a list via the API, the verification process will start automatically. If your credit balance is insufficient, the verification of your list will fail. You can purchase credits from the portal.

If an error occurs, the response will look like the below example:

The failure description may vary depending on the type of fail action. Examples of common failure messages are:

• Token invalid or does not exist
• The data format is wrong (when passing the data directly)

Once you receive a response, you will want to store the value of the token, as it will be used to check the status and eventually retrieve the results.

Checking the file status

Now that your list is running, you will need to poll the API and check the status periodically. For the first status check we recommended to wait approximately one minute until our cleaning system begins processing the file. For smaller lists (<50k) polling every 5-10 seconds is acceptable, but for larger lists (>50k) you’ll want to poll less frequently.

Request Status

In the response, the status parameter will indicate what the list is currently doing. Typically, status will be the only parameter you will need to watch. However, you may find the additional fields useful for monitoring list progress or to view a breakdown of the results in your list while it’s processing.

"status" : This top-level job progress field contains one of four possible conditions. Shown below are these possible conditions and associated descriptions.

• "Fail" - The cleansing process has failed and cannot complete the process. Action to take: Review the submitted data and retry if it did not follow the data format.
• "Pending" - The job is in the queue waiting for the process to start.
• "Running" - Your list has been imported and has begun the cleansing process. For additional job progress, follow the checkpoint field for additional detail.
• "Success" - Your list has completed and is ready for use. Action to take: Use pickup URL to download the results contained within a compressed file.

"checkpoint" : If you wish to follow the cleansing process in greater detail and the status condition = running then use the checkpoint field to determine job progress. Below are the possible condition descriptions.

• "Importing" - Cleansing job has started the import of your list.
• "Cleaning" - Cleansing job has imported your list and has begun the cleansing phase.
• "Classifying Results" - Classifying results and preparing report.
• "Cleansed" - Cleansing job has completed Classifying Results phase and will begin exporting results.
• "Exported" - Cleansing job results are ready for pickup.

Once the status value is set to success, you may begin retrieval of the results.

Retrieving the Results

Now with the cleansing process complete, it’s time to view our findings.

Downloading Results

The data will be returned in a zip file containing the results.

Example: SampleFileAPI.zip

The following export files contain the full row of fields initially provided in comma-delimited or CSV files unless noted otherwise:

	Cleaned. Once a file has completed processing, it will be placed in this folder as a compressed (zip) file of the same name as the original file.
		Within the compressed file you will find the following files and folders:
			SampleFileAPI-CERTIFIED.csv (20,000) All email addresses in this file have been certified good to send. You may upload this list to your ESP and send to each address with full confidence.
			SampleFileAPI-DISCRETIONARY.csv (0) We are able to conclude that these email addresses do not represent a threat to your online reputation, yet we are unable to conclusively verify that these addresses are deliverable. In order to provide to you additional detail and insight into the results obtained, we also include the following sub-classifications: Catch-All, Greylisted, Connection Timeout and Indeterminate. We advise sending this group initially on a separate network (domain/IP) to confirm bounce ratio is within acceptable norms before sending through your main sending network.
			SampleFileAPI-SUPPRESS.csv (10,000) All addresses in this file should be entirely removed from your active mailing list as they have been classified as “Do Not Email.” These addresses contain various reputation and deliverability threats and should be avoided. You may use this list as a suppression file to be uploaded to your ESP for ease of use. This export contains the following threat classifications: Trap, Mole, Quarantine, Seed (Bots/Role/Disposable/Seed/Dormant), Key, Parked, Invalid.
			SampleFileAPI-REPORT.html HTML File containing a link to this report (List Profile Report).

All file exports are formatted following the same field structure as provided with an additional field appended named “mxgroup” (Certified and Discretionary) or “threatclass” (Suppress). These file exports are sorted in ascending order (A-Z) using one of the two appended fields.

The “mxgroup” field identifies the domain/ organization responsible for handling the reception and acceptance or filtering of email for that particular email address. For more information, see Delivery Group section.

General Disclaimer: Every reasonable effort is made to locate all known threat and delivery classification elements mentioned herein, yet due to the constantly changing and dynamic nature of the online environment, we can not guarantee the results or deliverable will be free of any/all traps, threat or delivery classification elements identified within this report.

While every attempt has been made to ensure that the information in this document is accurate and complete, some typographical errors or technical inaccuracies may exist. Impressionwise does not accept responsibility for any kind of loss resulting from the use of information provided.

Questions? Please feel free to reach out with any questions you may have about our cleansing process or your results, and we look forward to you experiencing the results that truly set Impressionwise apart!

URI Advisories

Short for Uniform Resource Identifier Blacklist”., is a company/ website that produces a list of domain names observed sending spam or other undesired email content.

As subscribers to the URI advisory, ISPs and companies will know from which domain names appearing in the email from which to block traffic. Most traffic blocking occurs during the SMTP connection phase. The receiving end will check the URI for the connecting or sender domain name. If the domain name matches one on the list, then the connection gets dropped before accepting any traffic from that email sender.

For a complete understanding of the blacklisting process and how it can affect your email delivery as well as your sender reputation, see our Understanding Email Blacklisting help doc.

The various URI’s have different policies yet generally encompass the three major points:

• Goals. What does the URIBL seek to list? Is it a list of open-relay mail servers or open proxies – or of IP addresses known to send spam – or perhaps of IP addresses belonging to ISPs that harbor spammers?
• Nomination. How does the DNSBL discover addresses to list? Does it use nominations submitted by users? Spam-trap addresses or honeypots?
• Listing lifetime. How long does a listing last? Are they automatically expired, or only removed manually? What can the operator of a listed host do to have it delisted?

Impressionwise maintains the largest most complete knowledgebase of known anti-spam, URI or domain-based blacklists that can affect your online sending reputation and deliverability of your emails.

Highlights include detailed information for each site:

• Site name and description
• Threat-level
• Nomination process
• Listing lifetime
• Delisting guidance

Blacklist profiles

To view our knowledgebase of known anti-spam, URI or domain-based blacklist profile select from one of the following below.

Abuse.ro Reputation Services foobar.hu DNSBL Hostkarma DNSBL Improware Swinog DNSBL Invalument DNSBL nsZones.com DNSBL SARBL - Smart Adaptative Realtime URIBL Scientific Spam DNSBL

Spam Eating Monkey Suomispam Reputation Database SURBL URI Reputation Data The 0Spam (Zero Spam) Project The Spamhaus Block List Tiopan Blacklist URIBL.com ZAPBL

For additional guidance or any questions you may have, please contact us.

RBL Advisories

Short for Realtime Blackhole List, is a company/ website that produces a list of IP addresses observed sending spam or other undesired email content.

As subscribers to the RBL, ISPs and companies will know from which IP addresses to block traffic. Most traffic blocking occurs during the SMTP connection phase. The receiving end will check the RBL for the connecting IP address. If the IP address matches one on the list, then the connection gets dropped before accepting any traffic from that email sender.

For a complete understanding of the blacklisting process and how it can affect your email delivery as well as your sender reputation, see our Understanding Email Blacklisting help doc.

The various RBL’s have different policies yet generally encompass the three major points:

• Goals. What does the RBL seek to list? Is it a list of open-relay mail servers or open proxies – or of IP addresses known to send spam – or perhaps of IP addresses belonging to ISPs that harbor spammers?
• Nomination. How does the RBL discover addresses to list? Does it use nominations submitted by users? Spam-trap addresses or honeypots?
• Listing lifetime. How long does a listing last? Are they automatically expired, or only removed manually? What can the operator of a listed host do to have it delisted?

Impressionwise maintains the largest most complete knowledgebase of known anti-spam, RBL or IP-based blacklists that can affect your online sending reputation and deliverability of your emails.

Highlights include detailed information for each site:

• Site name and description
• Threat-level
• Nomination process
• Listing lifetime
• Delisting guidance

Blacklist profiles

To view our knowledgebase of known anti-spam, RBL blacklist profile select from one of the following below.

Abuse.ro Reputation Services Alligate-MXRate Sender Reputation Service Barracuda Reputation Block List (BRBL) Blocklist.de Fail2ban Reporting Service CHOON.NET DNSBL/RBL Comodo KoruMail Reputation Service Composite Blocking List (CBL) DNSBL - A User Unknown Blocking List DNSRBL - The Real-time Blackhole List Dr.MX RBL Fabel Spamsources information foobar.hu DNSBL GBUdb.com Hostkarma DNSBL IBM's DNS Blacklist ImproWare Spamlist Improware Swinog DNSBL Invalument DNSBL JIPPG's Relay Blackhole List Project JustSpam.org KONSTANT Blacklist Lashback's Bblacklist Lugh.ch RBL Mailspike RBL MegaRBL.net MSRBL - Realtime Black Lists NiX Spam RBL NoSolicitado.org RBL nsZones.com DNSBL Passive Spam Block List

Pendantic.org RBL Project Honey Pot (http:BL) Proofpoint Protected Sky RBL2.TRIUMF.CA realtime blackhole list RBLDNS.ru realtimeBLOCKLIST.com realtimeBLOCKLIST.com S5h.net RBL Scientific Spam DNSBL SINGULARis Spam/scam blocklist Spam Eating Monkey Spam Grouper Spamcop.net (SCBL) SpamRATS (Really Annoying Trouble Spots) Blacklist st.technovision.dk - The Technovision SpamTrap Suomispam Reputation Database The 0Spam (Zero Spam) Project The Kempt.net DNS Black List The South Korean Network Blocking List The Spam and Open Relay Blocking System (SORBS) The Spamhaus Block List Tiopan Blacklist UCE Protect Network Blacklist V4BL.org WebIron RBL Weighted Private Block List Woody's SMTP Blacklist

For additional guidance or any questions you may have, please contact us.

Blacklist Removal Process

For a complete understanding of the blacklisting process and how it can affect your email delivery as well as your sender reputation, see our Understanding Email Blacklisting help doc.

Determine why you are listed

Each blacklist has their own listing criteria that may include technical listings, policy listings, and evidence based listings.

Technical listings - are those that occur mostly from mail server configuration issues such as missing or incorrect reverse DNS records, missing on incorrect banner greetings, and mail servers operating in IP address space that an ISP has specified that mail servers should not be operating in.

Policy listings - are those based on an operator that does not wish to receive email from certain countries, or ISPs, or has a history of not honoring unsubscribe requests.

Evidence based listings - are those where the operator has receive direct (or indirect) evidence that an IP address has been involved in sending unsolicited emails.

For additional guidance, Impressionwise maintains the largest most complete knowledgebase of known anti-spam, IP and domain-based blacklists that can affect your online sending reputation and deliverability of your emails.

Resolve the underlying issue(s)

Once you have determined why an IP address has been listed you can begin your internal process of resolve the issue. This is a good time to confirm that your network, mail server, and computers are properly configured. Common resolutions include: fixing forward and reverse DNS records, STMP banners, scanning all machines on the network for viruses, patching operating systems, configuring routers more securely, and enforcing strong passwords.

Follow the blacklist removal process

After you have fixed the issues you'll need to go back to the blacklist's website and follow their specific removal process.

Self-service removal - Some blacklists have a self-service removal feature. These generally allow for near immediate removal from the blacklist. Be sure that you've resolved the issue before doing this. When an IP address gets listed again after removal the process can become more difficult.

Time-based removal - Most blacklists do not offer self-service or manual removal. They have a process that runs that will automatically remove low-level listings within a week or two. If the IP address has been involved in sending spam multiple times or in high volumes this process may take longer.

Things to keep in mind when contacting a blacklist operator

Don't lie - Don't tell the operator you've resolved the problem when you haven't. If you lie that you've resolved the issue and it happens again they will likely not talk to you anymore.

Keep it polite and professional - When you are having difficulty in removing a listing let them know what you are trying to do to resolve the issue. The more professional you are with them the more they'll be willing to help you resolve the issue. They are trying to stop people from receiving spam, not trying to keep you from legitimate non-spam correspondence.

For additional guidance or any questions you may have, please contact us.