The ‘UNIX software’ Archives
Posted February 9, 2004 by

Send Mail Via Telnet /Test for Open Relay

Behind the scenes, the commands sent to mail servers are simple text commands. These commands can be sent to an email server manually via Telnet. This is a quick way to test an email server to determine if it is an open relay.

Category Sendmail

Posted January 30, 2004 by

Rsync over SSH

The combination of rsync and ssh is a very efficient and secure method of moving and backing up data.

Category UNIX software

Posted January 30, 2004 by

SSH Public Key Usage

The following describes the creation and distribution of SSH public keys for ease of access to remote machines.

Category OpenSSH

Posted January 4, 2004 by

DNS/BIND resource record: using $GENERATE to make many records

A cool feature in versions of BIND since 8.2 and 9.1 is the $GENERATE directive which can create hundreds or thousands of resource records with a single line in zone file. A common use for $GENERATE is assigning PTR records for a DHCP address range.

Category BIND and DNS

Posted January 4, 2004 by

DNS/BIND resource record: CNAME, canonical names, host aliases

A single host may have multiple personalities: web server (www), mail server (mail, mx), dns server (ns), ftp server (ftp). Rather than assign each of these names an address (A) record pointing to the same IP address, all of which would need to be changed if the IP address changed, one name can be associated […]

Category BIND and DNS

Posted January 4, 2004 by

DNS/BIND: set TTL for individual resource records

BIND resource records allow an explict TTL value that will override the zone file’s TTL for that specific resource record. One use for this is to prevent non-authoritative servers from caching these records, perhaps in prelude to changing a server’s IP address.

Category BIND and DNS

Posted January 4, 2004 by

DNS/BIND Resource Record: Routing Mail with MX Records

Proper DNS configuration with MX records is a requirement for routing email for a domain.

Category BIND and DNS

Posted January 4, 2004 by

DNS/BIND resource record: PTR reverse lookup record

The PTR (pointer) record maps an IP address to a hostname and fully qualified domain name. Many applications use reverse lookups to identify the domain from which a TCP/IP connection is formed. Best practice for DNS is to create a PTR record for every A record.

Category BIND and DNS

Posted January 4, 2004 by

DNS/BIND Resource Record: Address (A) Record

The address record (A record) maps a hostname and fully qualified domain name with an IP address.

Category BIND and DNS

Posted January 4, 2004 by

DNS/BIND: Create a Basic Zone File

A zone file holds the DNS resource records for all of the domain names associated with the zone. Zone files store all of the data served by a DNS server. This recipe describes the basic zone file format without any resource records suitable for any type of zone file.

Category BIND and DNS

Posted December 9, 2003 by

Connect VNC client through a Putty SSH tunnel

Using tunnels with SSH is a powerful method to access services on systems behind a firewall or that are otherwise inaccessible. In this example, a VNC client on your local computer will connect to a remote VNC server (vncserv.tech-recipes.com:0) using port forwarding with an SSH connection to another remote host (sshd.tech-recipes.com).

Category UNIX software