MSN blocking PMTUD

Hi, it seems that Microsoft Network is blocking the path MTU discovery (ICMP fragmentation required but df bit set). That is causing problems because some customers who happen to use GRE tunnels for their branch offices can't access MSMessenger of the Hotmail page. Is there somebody from MSN here? Is there a workaround for this problem without using other type of tunneling? If not, is there any other workaround? -- Miguel Mata-Cardona Intercom El Salvador mmata@intercom.com.sv voz: ++(503) 278-5068 fax: ++(503) 265-7024