Error :

Received the below error when starting NGINX server,

# /etc/init.d/nginx start


nginx: [emerg] ,bind() to 0.0.0.0:80 failed (98: Address already in use)

nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)

nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)

nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)

nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)

nginx: [emerg] still could not bind()

Solution  1:

By default IPv6 TCP socket also accepts IPv4 traffic using the IPv4 structure. Need to disabled IPv6 service or  disbaled in configuration file linke below,
 
listen 80;
listen [::]:80 ipv6only=on default_server;

If you will face this error again try to follow the below steps,

Solution 2:

Find PID:

check the Nginx running Process id (PID) using fuser command,
 
#  fuser -n tcp 80
80/tcp:              12943 12955

Stop / Kill :
kill that PID by the below command,
 
# kill -9 12943
# kill -9 12955

Start Now:
 
# /etc/init.d/nginx start

Verify the Process:
 
# ps aux | grep nginx



root      9975  0.1  0.0 5948980 3924 ?        Ss   11:14   0:00 nginx: master process /usr/local/sbin/nginx -c /etc/nginx/nginx.conf

nobody    9981  0.2  0.1 5953584 6860 ?        S    11:14   0:00 nginx: worker process                         

nobody    9982  0.0  0.1 5951248 6488 ?        S    11:14   0:00 nginx: worker process                         

nobody    9983  0.0  0.0 5949128 4412 ?        S    11:14   0:00 nginx: cache manager process                  

nobody    9985  0.0  0.0 5949128 4296 ?        S    11:14   0:00 nginx: cache loader process                   

root     10064  0.0  0.0   6372   680 pts/0    S+   11:14   0:00 grep nginx