On Tue, 11 September 2001, Bill Woodcock wrote:

FWIW, I'm getting the voice-telco equivalent of an ICMP administratively-prohibited when trying to place voice calls from San Francisco to Moscow on AT&T LD. I'm curious whether this is a generalized policy or whether I'm just encountering a specific failure with a mis-matched error message.

Network Management Controls (i.e. call gapping) seem to be in effect for most international destinations. I don't think all calls are blocked, just 1 in N are getting a blocked recording on the first switch instead of going through the entire network. Sometimes if you use a different carrier (10-10-xxx) you'll get around the NMC.