Inordinate cmd read processes, jamming server

[queuebert]

I see these fairly frequently in my process list but they're usually not an actual problem to smooth operation. Today, suddenly, they are. There are a lot of processes that end with cmd read and they just hang out there. I have pasted a few examples from the output of "ps aux", there are actually enough of them to start making my server reject new connections. I expect a large amount of communication to go on with bigfish.com hosts as they are my spam filter providers, but I'd like it if they let my server know when they're done.

Can someone explain to me what's actually supposed to be occurring when a process is doing a "cmd read", and what might be going to to prevent the process from ending? I'd tremendously appreciate any help.

root 11149 0.0 0.5 6684 2884 ? Ss 12:05 0:00 sendmail: rejecting connections on daemon MTA: 50 children, max 50
root 11245 0.0 0.7 6860 3620 ? S 12:07 0:00 sendmail: server mail-dub.bigfish.com [213.199.154.10] cmd read
root 11247 0.0 0.7 6864 3564 ? S 12:07 0:00 sendmail: server mail-dub.bigfish.com [213.199.154.10] cmd read
root 11251 0.0 0.6 6856 3556 ? S 12:07 0:00 sendmail: server mail-dub.bigfish.com [213.199.154.10] cmd read
root 11281 0.0 0.7 6860 3560 ? S 12:07 0:00 sendmail: server utilnj01.rightnowtech.com [63.240.89.31] cmd read
root 11290 0.0 0.7 6860 3620 ? S 12:08 0:00 sendmail: server mail-dub.bigfish.com [213.199.154.10] cmd read
root 11319 0.0 0.6 6732 3528 ? S 12:09 0:00 sendmail: server delfino.haque.net [207.44.236.29] cmd read