Description of problem:
Scenario1:
ADSL connection --- CISCO ADSL router --- Linux server --- private network
Scenario2:
ADSL connection --- Alcatel modem --- Linux server/firewall --- private
network
Scenario3:
ADSL connection --- Alcatel modem --- Linux firewall --- Linux server ---
private network
Scenario4:
ISDN connection --- Linux firewall --- Linux server --- Linux firewall ---
private network
Problem the Linux server in (1) and (2) will not connect properly to
certain mail servers (usually telcos). Also "telnet mailhost5.wcom.com.hk
25" does not work (it says: "Connecting to <ip address of the machine>",
but doesn't - tcpdump reveals that it sends packets but does not receive
any). The funny part is that in (1) it works properly from both, the
CISCO router AND from the internal network. With (2) it works properly
from the internal network.
(3) and (4) work fine under all circumstances.
(1) and (2) use 2.4.17, 2.4.18
(3) uses 2.4.17 on the firewall and 2.2.? on the inside
(4) uses 2.4.17 on the firewalls and 2.4.? on the server
It appears that as long as the mail server has a Linux box forwarding
packets for it then it will work...
It also appears that all of the servers it has problems with do run a M$
OS - which I can't fix ;-)
Is there anything else I can try, to narrow down the area to look at?
Is there something obvious I might be doing wrong?
tom.
Consultant
AUSSEC Phone: 61 4 1768 2202
339 Blaxland Rd., Ryde NSW 2112
Email: tom@xxxxxxxxxx
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