We've had this firewall in place for years, and there haven't been changes to it in the past few months. Last week, however, we started having problems accessing one of our networks through the PIX, and after working with Microsoft, we determined it was an MTU issue. The maximum sized packet to the PIX and through the PIX is 1020 bytes, and it doesn't matter if the packets are sourced from a server or the PIX itself. From the server, we can ping 1500 byte packets to the core switch with no issues. All interfaces are set for 1500 byte MTU as shown in the following:
mtu outside 1500
mtu inside 1500
mtu dmz2 1500
Has anyone else run into this? I'd like to add we see this through the PIX and not just to it. Thank you.
