Sendmail + Firewall.

[Plagianakos Vassilis]

Geia sas. Sorry prokatabolika gia to megalo email, alla einai ligo 
mplegmeno to senario!

Skeftomai na ylopoihsw to akoloy8o sxhma gia to email:
           --------------
           |  Internet  |
           --------------
                  |
                  |
           --------------   --------------   --------------
           |  Firewall  |---|    DMZ     |---|    HostB   |
           --------------   --------------   --------------
                  |
                  |
           --------------
           | InternalLAN |
           --------------
                  |
                  |
           --------------
           |    HostA   |
           --------------

O HostB einai o dhlwmenos MX server toy domain moy gia ton e3w kosmo.
O HostA 8elw na exei ta mailboxes twn xrhstwn.
Oi xrhstes 8a stelnoyn email dhlwnontas SMTP ton HostA.
Oi HostA kai HostB 8a exoyn RedHat Linux 7.2, me sendmail.

Ta pleonekthmata einai profanh: o MX toy domain profylasetai apo to 
firewall kai ta emails twn xrhstwn briskontai "asfalh" se ena eswteriko 
mhxanhma poy mporw na exw pio kalo elegxo (backup ktl). Epishs, ston 
HostB 8a trexei kapoio antivirus, gia na eimai sigoyros oti ta email 
sto eswteriko diktyo einai xwris viruses.

Mia idea gia na ginoyn ola ayta ta kala einai sto /etc/mail/mailertable
toy HostB na dhlwsw ton HostA kai na epitrepsw apo to /etc/mail/access 
toy HostB to relay gia ton HostA (kobontas to relay gia to ypoloipo 
domain). Telos, dhlwnw ston HostA SMART_HOST ton HostB, kai epitrepw 
relay gia to eswteriko diktyo. 

Yparxei kamia kalyterh idea h' allh lysh??

To senario ayto exei to meionekthma oti otan ena email ftasei sto HostB
aytos 8a to prow8hsei ston HostA. To connection 8a einai apo thn DMZ 
pros to eswtreriko, pragma poy den moy aresei poly. Mporw na to apofygw 
ayto, xwris na prepei na trexw kai alloys servers (POP, IMAP ktl) ston 
HostB?? Dhladh 8a h8ela na 3ekina connection apo ton HostA (p.x. ka8e 
5 min) pros ton HostB...


Ka8e idea/skepsh eyprosdekth ;-)
TIA,

Vassilis.