Didn't get any responses; trying one more time. Thanks, all: We have Exch 5.5 on one W2K Server, and Exch 2000 on the other. Sometimes, not always, the two domains are not accessible to each other, despite the fact that trust has been established between the two domains. Has anyone experienced problems with a similar setup? Thanks for any input or research locations. List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm