It is very common that Linux server seems to hang when starting services such as Sendmail/Postfix or httpd.

The main cause for this is failure to resolve hostname i.e. Linux cannot look up the name of the machine/server via DNS lookup. Your server will boot but it will take some time and service may not work perfectly.

First, make sure the file /etc/resolv.conf has the correct values for your machine’s DNS (NS1 and NS2) server ip address:

$ cat /etc/resolv.conf

Output:

nameserver 202.54.1.20
nameserver 202.54.1.22

If you are not sure about correct nameserver IP then ask your network/sys administrator for correct IPs.

Another solution is to add your hostname to /etc/hosts file, which is the static table lookup for host names.

$ cat /etc/hosts

Output:

127.0.0.1          localhost.localdomain localhost
192.168.1.21       www.cyberciti.biz portal
192.168.1.254      router.cyberciti.biz router
192.168.1.25       laptop.cyberciti.biz lappy

Above method is quite useful if you are using Linux on a network without a DNS server. If you are going to configure 192.168.1.21 as the DNS server then you need to add your hostname to /etc/hosts file.