"Unknown host" ?!

Hi all. I'm running into the most incredibly annoying problem I've ever encountered (for the past week at least). I connect to the Internet via a modem and am dynamically assigned IP addresses by my ISP. Naturally, then, I use their SMTP server for sending mail. Every now and then when I try to send mail using VM, Emacs will pause for half a minute and then come back saying that my SMTP server's hostname is an unknown host. I know it's not because I've used it for years. Occasionally, GNUS does something similar as well, so I don't think it's a VM problem either. What's going on here? I compiled my own XEmacs on Mandrake 6.1, so I don't think there's a library problem. I've even tried to put in the IP address of the SMTP server in /etc/hosts, so I don't think it's any kind of DNS issue. Does anyone have any idea what's going on? I'd appreciate any help anyone can give. My email setup, for reference: ;; ;; Mail ;; (setq user-full-name "Gerald Gutierrez") (setq user-mail-address "gutier(a)intergate.bc.ca") (setq mail-self-blind t) ;; SMTPMAIL (setq send-mail-function 'smtpmail-send-it) (setq smtpmail-default-smtp-server "smtp.intergate.bc.ca") (setq smtpmail-smtp-service "smtp") (setq smtpmail-local-domain nil) (setq smtpmail-code-conv-from nil) (autoload 'smtpmail-send-it "smtpmail") ;; VM (autoload 'vm "vm" nil t) (autoload 'vm-mail "vm" nil t) (setq vm-use-toolbar nil) (setq vm-mutable-windows t) (setq vm-mutable-frames nil) (setq vm-primary-inbox "~/d/vmmail/inbox") (setq vm-crash-box-suffix ".crash") (setq vm-spool-file-suffixes (list ".spool")) (setq vm-folder-directory "~/d/vmmail/") (setq vm-spool-files (list (list "~/d/vmmail/inbox" "~/d/vmmail/inbox.spool" "~/d/vmmail/inbox.crash") ))