[Fwd: [imp] Can't send messages though sendmail]

[EdwardSPL at ita.org.mo]

Eric Rostetter wrote:

> Quoting EdwardSPL@ita.org.mo:
>
>    ----- Transcript of session follows -----
> 550 5.1.2 [edward@123.com]... Host unknown (Name server: 123.com]: host not found)
>
> Try the same command without the [ ] characters.  If it still fails, then
> it is a DNS/hostname problem, meaning either you didn't configure your
> /etc/resolv.conf, and/or you need to add 123.com to your /etc/hosts file.

Is it the problem of DNS ?

About our system :
Server A ( host1.123.com ) : imap server  + Sendmail ( redhat 6.2 ) + DNS
Server B ( host2.123.com ) : Web Server + IMP WebMail System ( redhat 7.2 )

In host1.123.com machine, /etc/resolv.conf :
domain 123.com
search 123.com
nameserver 202.175.xxx.xxx

In host2.123.com machine, /etc/resolv.conf :
domain 123.com
search 123.com
nameserver 202.175.xxx.xxx

So, how can I modify the config of DNS between host1.123.com and host2.123.com ?

Thank for your help !

Edward.