RBL / Block Lists. BigCity Networks, Inc. (BCN), in response to the increasing amount of incoming spam complaints from our customers and subscribers, has implemented additional resources to limit incoming spam (Unsolicited Commercial or Bulk E-mail). BCN has been using a limited form of localized blocking lists since BCN's inception, and this is simply an extension of that policy, designed to alleviate the ever-growing issue of incoming abusive spam attacks on our mail infrastructure. The enormous amounts of incoming spam were affecting BCN's ability to provide our customers with quality and consistent service levels, and we were forced to take proactive steps to address this issue.

With these rules in place, if someone sends an e-mail message and the sender's IP address or SMTP (mail) server is on one of these lists, then the incoming e-mail is blocked. The introduction of this tool may result in the inadvertent blocking of some e-mail that is not traditional spam.

The lists which are currently in use are:

Open Relay DataBase List (http://www.ordb.org)
Distributed Server Boycott List (http://dsbl.org/main)
SpamCop Block List (http://bl.spamcop.net)

These lists, coupled with a nationally maintained block list, will filter all inbound SMTP (e-mail) traffic. If an incoming e-mail is denied, a system message is NOT sent back to the sender. The email is tagged and stored in our spam filtering system. Once per day you will receive an email notification containing a list of all the filtered email messages stored for you. You can use the provided links to have any particular item sent to you, as well as notify us that it was filtered incorrectly. You can visit http://mailgate2.bigcity.net and see your filtered spam mail at any time, specifically if you do not want to wait for your daily email. The email is not stored forever, we maintain 7 days worth of stored junkmail for each account and then it is permenantly deleted. If you wish, we can remove the junk mail filtering from your account. If you need assistance, please email help@bigcity.net or call us, 713.228.0529 x3.

BCN subscribes to these lists because they help us to decide whether we want to accept or reject email from a given source. This is a decision which is made here at BCN; the list owners does not make this decision for us. The lists themselves lists do not block email - all they does is tell us which IP addresses are suspect in their mailing practices. It is up to us, BCN, to decide whether or not to block email from an IP address listed in any of these lists. BCN has the ultimate ability, in all cases, to make the final determination, as well as technical ability, to choose whether or not to accept e-mail from any Internet entity, including those listed in the MAPS or Spamhaus Lists.

BCN uses the information in these lists to block email coming from IP addresses which abuse Internet resources by sending massive quantities of unsolicited commercial or bulk email (commonly known as "spam"). This helps us to keep a significant amount of unwanted commercial e-mail from clogging our system, and assists us in solving a problem that is negatively impacting our customers.

BCN also maintains a local block list, separate from these lists. The error message in these local block lists will be specific enough so that an ISP can contact BCN Security to get the block removed. This list is used mainly in cases of immediate denial-of-service spam attacks, as an immediate reactive measure to stop an incoming spam attack. We will work with the ISP involved to address each situation.

In order for those entities who are currently on one of the third-party lists to be removed, they must contact that entity directly. Depending on the type of block, this can be either via telephone, or via the home pages of those entities. In most cases, a system that is on one of the lists is easily removed, following some simple steps. If you would like to know if a mail server is located on the lists that BCN utilizes, please see the URLs above.

BCN Inbound Sending Policy

Technical Guidelines:

• All e-mail must be RFC compliant. (Refer to http://www.rfc-editor.org)
• All e-mail servers connecting to BCN's relay servers must have valid reverse DNS entries (i.e. all sending IP addresses must have active corresponding domain names in DNS).
• All e-mail servers connecting to BCN's mail servers must be secured to prevent unauthorized use (may not be an open proxy, router, or relay).
• Connections from dynamically assigned IP addresses (dial-up accounts) will not be accepted to BCN's relay servers.
• Organizations may not hardcode BCN's mx records into their configuration files.
• Organizations must immediately unsubscribe any BCN e-mail addresses that receive a permanent failure e-mail bounce from BCN's mailer-daemon.

E-mail formatting Guidelines:

• Organizations must not do anything that tries to hide or forge the sender of the e-mail and sending site of e-mail.
• Each mailing must specifically state how the BCN members' e-mail addresses were obtained (i.e. purchase from Acme tools, sign up for Travel discounts, etc.) and must state whether this is a one-time mailing or a reoccurring mailing. Additionally, such details as the date and time when the e-mail address was obtained along with the IP address must be available upon request.
• All mailing should contain simple and obvious unsubscribe mechanisms. While we recommend that this be in the form of a (working!) link to a one-click unsubscription system, a "reply to:" address may also be used. In this case we require that the address receiving those replies be valid.
• All e-mail must have valid non-electronic contact information for the sending organization in the text of each e-mail (phone number, physical mailing address, etc.). If this is not readily feasible, there must be a link in each e-mail to such information on the sending organization's Web site.
  Policy & Procedural Guidelines:
• All e-mail to BCN's member base must be solicited (i.e. there is an existing and provable relationship between the e-mail recipient and the sender).
• If an organization generates complaints, bounces 20% or more of the total recipients on its mailings, or has difficulty accepting those bounces, the BCN Security Operations group may implement blocks until a reconfirmation mailing is sent.

In no way does the posting of these guidelines imply any affiliation, membership, sponsorship or endorsement of business or activities/practices of an organization by BCN.

BCN reserves the right to discontinue delivery of e-mail from an Internet sender if BCN's service is impaired or for other reasons.

BCN Whitelist Policy

BCN realizes that utilizing any blocklist may result in the loss of requested and wanted email. In an effort to alleviate this, and to ensure that our subscribers receive mail that they have legitimately requested, BCN subscribes to multiple services listing senders who have certified, via some pre-defined mechanism, that all mail that they send is confirmed as having been requested by the recipient.

The lists that BCN currently subscribes to are:

Habeas (http://www.habeas.com)

BCN does not require that a given entity utilize the lists above, or utilize any particular mailing list style. If, however, a given entity is found to have sent unsolicited bulk or commercial mailings to our role accounts or subscribers, as described on our Mail Block page, they will be subject to the removal criteria specified therein. This policy extends to our use of the above listed RBL lists.

If a given entity does not "come into the radar screen" of either BCN, or the lists that BCN utilizes, then BCN will take neither positive nor negative action in regards to mailings from that entity.