Intro: DNSBLs
Intro: Reverse DNS New!
Monitoring
Alerts
Statistics and Reports
  • What are DNSBLs?

    DNSBLs (DNS-based Blackhole List, a.k.a RBL: Real-time Blackhole List) are lists of IP addresses published through Domain Name Servers which are mostly used to publish the IP addresses of computers or networks found to be spamming. Mail servers can be configured to reject emails sent from the IP addresses listed in these "blacklists".

    Where are other consequences of blacklisting/unintended spamming?

    Besides having your emails deferred from recipient email servers unwanted spamming will use precious network resources. Possibly leading to:

    • exceeded traffic limits,
    • extra traffic charges,
    • high bandwidth consumption, thus slower connections,
    • penalties from ISPs,
    • excesive computing resource (CPU, RAM) usage,
    • unwanted charges on cloud computing environments where computing resource usage is charged,
    • lower service quality, frowny faces.

    Where can I learn more?

    Below are some sites that have more information about DNSBLs.

    Which IPs should be monitered?

    It is a good idea to monitor the IPs of:

    • Mail servers
    • Web/application servers
    • Any servers providing services on the internet.
    • External IPs assigned to NAT points (DSL gateways, routers).

    How does an IP get listed?

    Different lists have different rules for the listing to occur. Possible reasons to get listed is listed below but may not be limited them.

    • The IP address is a source of spam.
    • The IP address acts as an open mail relay.
    • The IP address is an open proxy.
    • The IP address is assigned dynamically.
    • The IP address block is assigned to a spammer.
    • The IP address block is assigned to an ISP who is not acting on its spamming members.

    What are the possible unintented causes of listing?

    Some possible causes to get listed is listed below but may not be limited them.

    • Trojen or virus infection.
    • Weak email passwords.
    • Hackers
    • Misconfigured email or proxy server.
    • Misconfigured firewall.
    • Abusive usage.
    • Badly developed software.
    • Unusual high usage.
  • What is a Reverse DNS lookup?

    Reverse DNS (rDNS) lookup is finding the domain name (PTR record) that is associated with an IP address. You can find more information about rDNS lookups on Wikipedia.

    How and why would my rDNS change?

    Your rDNS is usually controlled by your ISP and can be changed by them. If you need to change it you should contact your ISP. Some ISP's can occasionally change your rDNS by mistake.

    What happens when my rDNS is changed?

    It may not make that much difference if you are just an ordinary user, but if you are providing services it may effect your users and services. Such that, email delivery rates may drop because some mailbox providers consider rDNS records when filtering email for SPAM and may reject email that are generated from IP's that do not match their reverse DNS records.

    What is the Reverse DNS / PTR record used for?

    Reverse DNS is mostly used for:

    • As an e-mail anti-spam method by checking the domain names in the rDNS to see if it is associated with the domain name of the email trying to be delivered (forward-confirmed reverse DNS (FCrDNS)).
    • To determine if the rDNS corresponds to a dynamically assigned addresses (such as dial-up or home ADSL users).
    • To provide human-usable data by using the rDNS instead of IP addresses in logs and applications.
    • Troubleshooting network problems using tools such as traceroute, ping, etc.
  • Manual and regular DNSBLs checks are time consuming.

    Even if you have a handful of IP addresses it's just not feasible.

    BLalert comes into action here. It checks all 135 DNSBLs every single day for 365 days and reports the results back to you.

    New! BLalert also monitors for changes in your rDNS. Keeping you aware of unwanted changes.

    135 DNSBLs
    Checked once a day
    For 365 days
    Unlimited alerts
    Unlimited contacts
    Alerts by e-mail or GTalk
    Detailed stats
    Downloadable data
    Regular reports
    New! rDNS monitoring included!

    $4.95

    per year, per IP

    30 Day Money Back Guarantee Seal

    Sign Up Now!

    Checking 10 IP addresses against 135 DNSBLs every day for 365 days is a total of 492,750 checks!

    If you try to manually check the 10 IP addresses against 135 DNSBLs every day, and lets say that every IP takes 30 seconds to check. It would take in total 30 hours to check them every day for 365 days.

  • You will be alerted if your IP gets blacklisted.

    Within 24 hours after listing, by email or by GTalk.

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    Alerts are sent right after the check is completed.

    We try to check all your monitored IPs at the same time. (Maximum 10 at a time.) So you will likely get all alerts in the same message.

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    We also alert you if your rDNS has changed. New!

    We check your rDNS record everytime we check for blacklisting and tell you if there is a change.

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    You chose when to get alerted.

    You can choose to be alerted if the IP gets listed and/or when the IP gets unlisted. You may also choose to be alerted after every check as long as its listed.

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    Either by email or by GTalk. Or both!

    Emails are standard. But you can also add GTalk contacts. You can be notified on your smart phone or through the desktop app?

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    You can add unlimited number of contacts to be alerted.

    Adding in the whole team or your customers contact is not a problem. You can also chose which contact gets which IP's alerts.

    135 DNSBLs
    Checked once a day
    For 365 days
    Unlimited alerts
    Unlimited contacts
    Alerts by e-mail or GTalk
    Detailed stats
    Downloadable data
    Regular reports
    New! rDNS monitoring included!

    $4.95

    per year, per IP

    30 Day Money Back Guarantee Seal

    Sign Up Now!

  • We love data.

    We keep 365 days of data for each IP we monitor and provide you with the statistics and regular reports.

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    Detailed statistics and graphs.

    We will keep every result of our checks for the last 365 days and provide you with graphs on how your IP address is doing. New! We also keep a history on your rDNS.

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    The data is yours.

    You can download the data in a CSV format anytime you want.

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    We send regular reports.

    Weekly, monthly or quarterly reports on how your IPs are doing. You decide which contact receives the reports.

    135 DNSBLs
    Checked once a day
    For 365 days
    Unlimited alerts
    Unlimited contacts
    Alerts by e-mail or GTalk
    Detailed stats
    Downloadable data
    Regular reports
    New! rDNS monitoring included!

    $4.95

    per year, per IP

    30 Day Money Back Guarantee Seal

    Sign Up Now!

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