레드헷 시리즈 부팅시 sendmail 서비스 시작 오래걸림 현상

https://www.centos.org/modules/newbb/viewtopic.php?topic_id=29490

centos에서 booting시 sendmail 시작 과정에서 시간을 많이 잡아먹는 경우가 있다.
이때 /etc/hosts 파일이 도메인 형식을 가지지 않아서 그렇다고 한다.

※you must fully qualified domain name(FQDN)
http://www.linuxhomenetworking.com/wiki/index.php/Quick_HOWTO_:_Ch21_:_Configuring_Linux_Mail_Servers
위 링크에 나온 내용

The /etc/hosts File The /etc/hosts file also is used by DNS clients and also needs to be correctly configured. Here is a brief example of the first line you should expect to see in it:

127.0.0.1 bigboy.my-site.com localhost.localdomain localhost bigboy
The entry for 127.0.0.1 must always be followed by the fully qualified domain name (FQDN) of the server. In the case above it would be bigboy.my-site.com. Then you must have an entry for localhost and localhost.localdomain. Linux does not function properly if the 127.0.0.1 entry in /etc/hosts doesn't also include localhost and localhost.localdomain. Finally you can add any other aliases your host may have to the end of the line.

예를 들어 위 링크의 변경된 내용이다.

My current hosts file:

Quote:
# Do not remove the following line, or various programs # that require network functionality will fail.
127.0.0.1 localhost.localdomain localhost
::1 localhost6.localdomain6 localhost6
10.3.0.1 main
10.3.0.2 alt1

Change /etc/hosts to:

127.0.0.1 localhost.localdomain localhost
::1 localhost6.localdomain6 localhost6
10.3.0.1 main.my-site.com main
10.3.0.2 alt1.my-site.com alt1

도메인은 그냥 형식적으로 아무거나 써줘도 된다. 테스트로 검증됨

아니면 sendmail 서비스를 꺼주는 방법도 생각해볼만 하다