HI List One of my clients is having problem sending mails to external smtp address from exchange which is behind ISA server. They have 10 computers network. configured with ISA and Exchange. Exchange is behind ISA. They user external SMTP server as smart host to send mails. they are using dialup internet connection on isa server computer. POP and SMtp ports are open in ISA server. any body in network can send ad recieve mails thru outlook which is not Exchange client. but the problem is when exchange outlook client wants to send mails thru exchange. mails do not go. they are qued in exchange. i tried to telnet external smtp from exchange machine. it connected. and if i use dial up on exchange machine. mails start gooing. what is the problem. Can anybody help me. Reg Shamshad