[Mimedefang] Intermitten Problems

[An.H.Nguyen]

Both of my Solaris sendmail gateways started to have some problems since 
Oct.14 when the "Possible SMTP attack: command=HELO/EHLO, count=3" appeared.

- Sendmail stops repsonding for a short time then came back, this happens 
several times a day
- milter-greylist process died, then it came back on by itself in about 5 
minutes, this also happens serveral times a day
- I can't fine /var/milter-greylist/milter-greylist.sock on one of my two 
servers, should I copy this file over? (It's size is zero and has a special 
permission settings srwxr-xr-x)

Some error messages (random picks, not in any orders):
    milter-greylist: [ID 552762 mail.error] greylist: accept() returned 
invalid socket (Too many open files)
    milter-greylist: [ID 879519 mail.warning] greylist: setsockopt() failed
    Milter (greylist): timeout before data read
    Milter (greylist): init failed to open
    Milter (greylist): error connecting to filter: Connection refused by 
/var/milter-greylist/milter-greylist.sock
    mimedefang-multiplexor[12219]: [ID 260045 mail.error] Reap: Idle slave 9 
(pid 25739) exited normally with status 255 (SLAVE DIED UNEXPECTEDLY)
    mimedefang-multiplexor[12219]: [ID 389462 mail.error] Slave 6 died 
prematurely -- check your filter rules
    mimedefang[12232]: [ID 847421 mail.error] Error from multiplexor: ERR No 
response from slave
    mimedefang[27731]: [ID 758488 mail.warning] mfconnect: Error 
communicating with multiplexor
    mimedefang-multiplexor[27727]: [ID 980602 mail.info] Slave 5 stderr: 
getservbyname failed for tcp at /usr/local/bin/mimedefang.pl line 529
    sendmail[18155]: [ID 801593 mail.warning] k9RFFCUM018155: collect: 
premature EOM: unexpected close
    sendmail[26774]: [ID 801593 mail.info] k9RHumxI026774: Milter 
(greylist): to error state

SW Versions:
Sendmail 8.12.10
mimedefang version 2.51
SpamAssassin version 3.0.3
  running on Perl version 5.8.0
milter-greylist: I'm not sure what version it is, help!..

I'm new to this environment, I take over from a previous sysadmin who left 
so I am desperate here...
I think about upgrading, but affraid to break things up. I have clone one of 
the gateways to a 3rd server and able to do testings on it.
Please help!
An Nguyen