[FW1] OT - How risky is it?

[Ivan Fox <ifox100@hotmail.com>]

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There are NT-based ftp, http and https servers running in the DMZ behind
a FW-1 firewall.  In other words, ports 21, 80, 443 are opened on the
firewall to allow incoming traffic.
 
Can competitors/intruders hijacked sessions, hack data, ip spoofing,
etc. on these servers?
 
Any comments/suggestions are greatly appreciated.
 
BTW, are there mailing lists discussing topics like these?
 
Best regards,
 
Ivan