Rick, The reason i used top was because I noticed that mailscanner and smtpd were always on the list UNLESS the issue was occurring. I will try ps + grep next time as well. As for the ips they resolve quickly however they are all listed in /etc/hosts as we do not have an internal DNS. -jr replies-lists-a1z2-centos at listmail.innovate.net wrote: > using "top" to look for processes probably isn't the best approach as > (by default) you'll only see the more resource intensive applications. > you'll probably get a better picture of things related to a specific > application using "ps" (and grep). > > when you connect to an MTA (e.g., postfix/sendmail) it will try to do > an reverse map lookup on the ipnumber of the inbound connection. if you > don't have in-addr.apra entries for your ipnumbers, or if the machine > running your MTA is having trouble getting to the dns server for the > ipnumber range, then you'll get the type of delays you seem to be > seeing. ultimately the dns will time out (the number of dns servers you > have listed in your mail server's /etc/resolv.conf will effect this - > more is not better). > > you can get a sense of whether this is the issue by doing lookups (on > the mail server) of the ipnumber(s) for connecting machines that are > encountering the delay. depending on your configuration, your server > may cache a result, so the first may be slow with subsequent ones > being fast (until you hit the TTL on the record). > > [by the way, when sending to a mailing list please try to suppress your > confidentiality notice as it's meaningless in this context, and takes > up a lot of lines.] > > - Rick > >