Will Pix change packet data?

[marcreiter]

I can see smtp data enter the pix 515e correctly (debug inside)however when it gets to the smtp server in the dmz the data field of the packet has changed to 2A(hex)'s (net monitor)

Will the pix change a packets payload? Why? How to fix? The syn ack part of the connection is fine only the smtp data is changed...

[nkhawaja]

fixup protocol smtp only allows commands per RFC821, other non RFC commands are changed.

See this link for further information.

http://www.cisco.com/en/US/partner/products/hw/vpndevc/ps2030/products_tech_note09186a00800b2ecb.shtml

Thanks

Nadeem

[marcreiter]

it is in the 220 (per rfc 821) response that the server identification string is changed. this is the first communication from smtp acknowleging a connection.