In this article I will give an example of detecting and blocking the sending of spam messages behind a NAT server.Continue reading “Blocking SPAM behind a NAT server”
If the DNS settings of any site have been changed and in order not to wait for the time to cache DNS records, you can manually clear them, after which the DNS client on MacOS will request new data from the DNS servers.Continue reading “How to clear DNS cache on MacOS”
In the Windows DNS cache, records of domain names with their IP addresses to which were accessed are stored. When a user opens a site for the first time, a DNS server is accessed; upon subsequent openings of a site, Windows already takes information from the cache. Therefore, if a new IP address has been assigned to a domain, then the system will access the old one for a while based on the data in the cache.Continue reading “How to clear the DNS cache in Windows”
In this article I will give an example of generating keys and adding DKIM records.Continue reading “How to add DKIM record”
DMARC recors allow recipients and senders to verify the authenticity of messages, as well as determine what to do with messages that are not DKIM validated.Continue reading “How to add DMARC record”
I will give an example of adding MX records in the DNS settings of a domain name registrar.Continue reading “How to add MX record”
Suppose Bind9 logs are written to the /var/log/named/ directory, have the .log extension and so that the disk space does not overflow with logs, configure logrotate.Continue reading “Logrotate Bind9”
I will give an example of installing the Unbound caching DNS server.
You can install Unbound in Ubuntu with the command:
Suppose the default INPUT DROP and a DNS server is installed, now I will give an example of IPTables rules so that clients can access the DNS server.
To open the DNS port in IPTables, let’s execute the rule:Continue reading “IPTables rules for DNS”
Dnstop allows you to make a list of hosts that most send requests to the DNS server, so you can detect viruses on the network and understand who is attacking.Continue reading “Dnstop – monitoring of requests to the DNS server”