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 * distributed with this work for additional information        *
 * regarding copyright ownership.  The ASF licenses this file   *
 * to you under the Apache License, Version 2.0 (the            *
 * "License"); you may not use this file except in compliance   *
 * with the License.  You may obtain a copy of the License at   *
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 * Unless required by applicable law or agreed to in writing,   *
 * software distributed under the License is distributed on an  *
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
 * KIND, either express or implied.  See the License for the    *
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 * under the License.                                           *
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package org.apache.james.transport.matchers;

import org.apache.mailet.GenericMatcher;
import org.apache.mailet.Mail;

import java.util.Collection;

/**
 * Does a DNS lookup (MX and A/CNAME records) on the sender's domain.  If
 * there are no entries, the domain is considered fake and the match is 
 * successful.
 *
 */
public class SenderInFakeDomain extends AbstractNetworkMatcher {

    public Collection match(Mail mail) {
        if (mail.getSender() == null) {
            return null;
        }
        String domain = mail.getSender().getHost();
        //DNS Lookup for this domain
        Collection servers = getMailetContext().getMailServers(domain);
        if (servers.size() == 0) {
            //No records...could not deliver to this domain, so matches criteria.
            log("No MX, A, or CNAME record found for domain: " + domain);
            return mail.getRecipients();
        } else if (matchNetwork(servers.iterator().next().toString())){
            /*
             * It could be a wildcard address like these:
             *
             * 64.55.105.9/32          # Allegiance Telecom Companies Worldwide (.nu)
             * 64.94.110.11/32         # VeriSign (.com .net)
             * 194.205.62.122/32       # Network Information Center - Ascension Island (.ac)
             * 194.205.62.62/32        # Internet Computer Bureau (.sh)
             * 195.7.77.20/32          # Fredrik Reutersward Data (.museum)
             * 206.253.214.102/32      # Internap Network Services (.cc)
             * 212.181.91.6/32         # .NU Domain Ltd. (.nu)
             * 219.88.106.80/32        # Telecom Online Solutions (.cx)
             * 194.205.62.42/32        # Internet Computer Bureau (.tm)
             * 216.35.187.246/32       # Cable & Wireless (.ws)
             * 203.119.4.6/32          # .PH TLD (.ph)
             *
             */
            log("Banned IP found for domain: " + domain);
            log(" --> :" + servers.iterator().next().toString());
            return mail.getRecipients();
        } else {
            // Some servers were found... the domain is not fake.

            return null;
        }
    }
}