We are experiencing some problems lately with a small number of webpages in the internet while accessing them behind a PAT address (many to one). The same web pages work fine if accessed behind a NAT address (one-to-one Translation).
We are using PIX 535 version 8.0(4), while we also tried it by "downgrading" to 7.2(4).
At the begining we suspected problem with DNS, but doesn'e make much sense since, the pages work well if behind NAT. Another assuption is to do with ICMP error that some web pages send back to source, but not handled if behind PAT by PIX, but we couldn't find anything in the capture...
The NAT/PAT we are using is.....
nat (USERS) 10 10.10.0.0 255.255.0.0
global (OUTSIDE) 10 X.X.X.0-X.X.X.X.61 netmask 255.255.255.224
global (OUTSIDE) 10 X.X.X.X.62 netmask 255.255.255.224
global (OUTSIDE) 10 X.X.X.X.63 netmask 255.255.255.224
And the following (default) policy....
dns server-group DefaultDNS
inspect h323 h225
inspect h323 ras
inspect icmp error
inspect dns preset_dns_map