xp ignores icmp messages

[Romko]

Hi,

I'm experiencing the following problem : win xp (lets say
compuetr A) is behind firewall (MS ISA). I'm connecting
to another computer (lets say B) through ISA. The network
connection from ISA to B has MTU 1350 bytes. When
connecting to B, ICMP message Destination unreachable
returns to computer A. This message tells A that the
packet is to large (1500 bytes) and that MTU on next hop
is 1350 bytes. Computer A then resends the packet again,
but it is still 1500 bytes long. I have also tried to set
the MTU on the ISA interface, but win xp keeps ignoring
the ICMP message.

Thanks in advance.

 

[Marc Reynolds [MSFT]]

Hi,

Are you sure that computer A is receiving the ICMP packets? Normally ISA
blocks all ICMP traffic. If you want to allow ICMP traffic through ISA you
need to specifically configure it.

274568 How to Enable Internet Control Message Protocol Proxy PING Requests
http://support.microsoft.com/?id=274568

Thanks,
Marc Reynolds
Microsoft Technical Support

This posting is provided "AS IS" with no warranties, and confers no rights.

 

[Paul Woodsford]

The WinXP firewall is deactivated?