Question regarding FLOCK or POSIX with Sendmail 8.13.x and MailScanner.

[Duncan, Brian M.]

>
> I can't tell you why your version is different, maybe a
> custom compiled version to get around the Flock exploit that
> was posted about the time 8.12.11 came out. The consensus so
> far has been ; Linux and sendmail 8.12 = flock Linux and
> sendmail 8.13 = posix Also note that there have been some
> problems with dovecot if it is set to a different locking.
>
> I am still curious as to how you have been so lucky with no problems!
> Are you running on a filesystem other than ext2/ext3?
> Maybe Core 4 has a kernel that doesn't have the locking
> problem that the enterprise distros lack because of the
> conservative patching that is done.
>
>

I use Ext3 on all of my mail boxes.  Maybe it is due to the kernel
somehow, or the sendmail RPM's that I used.  I am using the Fedora
compiled kernels.  I switched over to posix earlier on my servers and
have not noticed any differences Yet.  I have been keeping a close eye
on the /var/spool/mqueue folders.

I was more worried about having trouble switching to posix, since this
one box has passed probably close to 200 million messages without issues
with flock on.  I was feeling like if it's not broke don't fix it type
situation.  Yet I see allot of people running into this problem.

I have been trying to find a way to 100% determine what lock method
sendmail uses.  From scanning the mailing lists and searching allot of
people tell others to check with sendmail -d0.1 -d0.4 -bt </dev/null.

If it lists flock in the compiled options then it's using flock.  I have
NOT been able to confirm this.

Here is one host of ours that just rejects messages. (It is a Sendmail
8.12.x box, so it SHOULD be using flock from what I understand)

It was compiled from RPM on 03/08/06, I checked the SPEC file and see
nothing specifying lock type.  The only reason I updated this one was
due to an exploit at the time if I recall correctly.

Version 8.12.11.20060308
 Compiled with: DNSMAP HESIOD HES_GETMAILHOST LDAPMAP LOG MAP_REGEX
                MATCHGECOS MILTER MIME7TO8 MIME8TO7 NAMED_BIND NETINET
NETINET6
                NETUNIX NEWDB NIS PIPELINING SASL SCANF TCPWRAPPERS
USERDB
                USE_LDAP_INIT
 
This is my 8.13 boxes: (same on all of them)

Version 8.13.8
 Compiled with: DNSMAP HESIOD HES_GETMAILHOST LDAPMAP LOG MAP_REGEX
                MATCHGECOS MILTER MIME7TO8 MIME8TO7 NAMED_BIND NETINET
NETINET6
                NETUNIX NEWDB NIS PIPELINING SASLv2 SCANF SOCKETMAP
STARTTLS
                TCPWRAPPERS USERDB USE_LDAP_INIT

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