RE: openldap 2.1.3 libraries and udp

["Howard Chu" <hyc@symas.com>]

The netstat output you included indicates that these are sockets
established for DNS lookups. ldap_bind (and any function that deals with
hostnames) uses the resolver library to map hostnames to internet addresses.
This is an issue with your system's resolver library, not OpenLDAP.

  -- Howard Chu
  Chief Architect, Symas Corp.       Director, Highland Sun
  http://www.symas.com               http://highlandsun.com/hyc
  Symas: Premier OpenSource Development and Support 

> -----Original Message-----
> From: owner-openldap-software@OpenLDAP.org
> [mailto:owner-openldap-software@OpenLDAP.org]On Behalf Of Ben Higgins
> Sent: Wednesday, July 31, 2002 5:29 PM
> To: openldap-software@OpenLDAP.org
> Subject: openldap 2.1.3 libraries and udp
> 
> 
> I'm having a curious problem that's left me completely stumped.  I 
> have installed the openldap 2.1.3 libraries (no slapd or slurpd) 
> for use with PHP.  I am having a problem with UDP sockets being 
> created and not going away.
> 
> The problem seems to be with calling ldap_bind from PHP.  Whenever 
> I do this, a UDP socket is established from and to localhost.  
> There is, of course, also a TCP connection made to the LDAP server 
> (which is on another machine), and that is working just fine.  In 
> PHP, ldap_unbind and ldap_close are aliases for the same function. 
>  Still, I've tried calling both of them, and none of them remove 
> this UDP connection.
> 
> One new UDP connection is created for each ldap_bind, and this 
> connection never goes away, unless I stop httpd  (httpd -> PHP -> 
> openldap libs).  It's by chance I noticed that this was occuring 
> when I had some sloppy code that made hundreds of bind calls.  
> Soon my page wasn't loading and when I went over to the Linux box 
> it told me that too many files were open.  Sure enough apache had 
> hundreds of FDs for all these UDP connections.  (Funny thing 
> though, I had been running this code for awhile and this issue 
> should have cropped up before it did... I don't think I changed 
> anything...)
> 
> Example:
> I run a script that calls ldap_bind (and also ldap_unbind, but 
> that doesn't seem to have any impact) several times and this happens:
> 
> # netstat | grep udp | wc -l
> 122
> 
> 122 udp sockets established!  Maybe four or five of those aren't 
> caused from running the script.  All these connections look like 
> this (just imagine a lot more):
> 
> udp        0      0 localhost.localdom:3837 
> localhost.locald:domain ESTABLISHED 
> udp        0      0 localhost.localdom:3836 
> localhost.locald:domain ESTABLISHED 
> udp        0      0 localhost.localdom:3835 
> localhost.locald:domain ESTABLISHED 
> udp        0      0 localhost.localdom:3834 
> localhost.locald:domain ESTABLISHED 
> udp        0      0 localhost.localdom:3833 
> localhost.locald:domain ESTABLISHED 
> 
> I've waited several hours and they don't go away
> 
> I'm completely stumped.  I've also tried an older ver. of openldap 
> (2.0.25) with the same behavior.  Why are UDP connections being 
> created at all?  Why don't they go away?  Where in the code should 
> I look if I have to hack it myself?  Any ideas?
> 
> This is how I have openldap configured:
> 
> ./configure --prefix=/usr/local/openldap --disable-slapd 
> --disable-slurpd --enable-static --enable-shared --with-gnu-ld
> 
> Ben
> 
> 
>