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Re: Problem with firewall?

IEM - Network Operation Center wrote:

Andrew Afliatunov wrote:

Authentication fails, and in mail.log I see: -- Dec 24 11:24:15 web imapd[3408]: pam_ldap: ldap_simple_bind Can't contact LDAP server --

Here I must say, that when I built test Linux server in local network
with the same configuration and test Windows AD server in the same
network, I was able to authenticate in IMAP. The only difference between
WAN and LAN servers is firewall.
So - isn't it enough to open port 636 on it (although firewall log says
that ldap packets go in both directions)?

Thanks for your reply.

have you changed the ldap-servers address ;-) ?

Of course ;-).

are you sure that pam_ldap is using port 636 / SSL ?

In firewall logs packets go on ldap-server and back through port 636. (As I set in /etc/ldap.conf - 'port 636' and 'ssl on').

are the ports forwarded to the correct machine ?


try to connect to your ldap-server via "telnet remote.server 636"

web[/0]~#> telnet 636
Connected to
Escape character is '^]'.
(After a long time)
Connection closed by foreign host.
I don't think that windows allows telnet connections on port 636 (or 389 either).

try to connect to your ldap-server with some command-line tools like "ldapsearch" (on debian this is in ldap-utils; on slackware i don't know) and get some information

Ldapsearch works fine through port 389, but through 636 - 'ldap_bind: Can't contact ldap server.'
On my test servers situation is the same - ldapsearch on linux can't bind to windows port 636, but authentication of imap in AD nevertheless works there.

in the past, i have had problems with the certificates being not installed on the client-machine (your imap-server)

Windows server dosn't require client authentication, so there's no need in certificate on linux server. And I don't use TLS, but SSL.

furthermore, a lot of imap-servers have built-in ldap-support, so you could use this instead of pam. (i guess this is somewhat flamish on this list)

I like PAM, because with it I don't need to change software.
But if you can't suggest anything more, I'll have a look on other imap servers...

-- Andrew

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