Hi, I'm experiencing a problem that I think might be related to mod_authnz_ldap. I have a virtualhost configured with the following: ProxyPass /jobs/ http://backend.domain.co.uk/public/jobs/admin/ <Location /jobs/> AuthType basic AuthName "Jobs Administration" AuthBasicProvider ldap AuthLDAPURL "ldap://ldap.domain.co.uk:389/o=domain?uid?sub?(objectClass=inetOrgPerson)" AuthzLDAPAuthoritative on Require ldap-user username RequestHeader unset Authorization </Location> LogLevel debug </VirtualHost> Access generally works but occasionally returns a proxy error with a reason of 'Error reading from remote server' however a packet capture shows that Apache didn't even try to establish a connection to backend.domain.co.uk. I've upped the logging level to debug and the following is what's logged: [Mon Feb 04 11:06:54 2008] [debug] mod_authnz_ldap.c(373): [client 192.168.1.1] [28349] auth_ldap authenticate: using URL ldap://ldap.domain.co.uk:389/o=domain?uid?sub?(objectClass=inetOrgPerson), referer: http://admin.domain.co.uk/jobs/updated.asp [Mon Feb 04 11:06:54 2008] [debug] mod_authnz_ldap.c(454): [client 192.168.1.1] [28349] auth_ldap authenticate: accepting username, referer: http://admin.domain.co.uk/jobs/updated.asp [Mon Feb 04 11:06:54 2008] [debug] mod_authnz_ldap.c(611): [client 192.168.1.1] [28349] auth_ldap authorise: require user: authorisation successful, referer: http://admin.domain.co.uk/jobs/updated.asp [Mon Feb 04 11:06:54 2008] [debug] mod_proxy_http.c(54): proxy: HTTP: canonicalising URL //backend.domain.co.uk/public/jobs/admin/index.asp [Mon Feb 04 11:06:54 2008] [debug] proxy_util.c(1335): [client 192.168.1.1] proxy: http: found worker http://backend.domain.co.uk/public/jobs/admin/ for http://backend.domain.co.uk/public/jobs/admin/index.asp, referer: http://admin.domain.co.uk/jobs/updated.asp [Mon Feb 04 11:06:54 2008] [debug] mod_proxy.c(756): Running scheme http handler (attempt 0) [Mon Feb 04 11:06:54 2008] [debug] mod_proxy_http.c(1662): proxy: HTTP: serving URL http://backend.domain.co.uk/public/jobs/admin/index.asp [Mon Feb 04 11:06:54 2008] [debug] proxy_util.c(1755): proxy: HTTP: has acquired connection for (backend.domain.co.uk) [Mon Feb 04 11:06:54 2008] [debug] proxy_util.c(1815): proxy: connecting http://backend.domain.co.uk/public/jobs/admin/index.asp to backend.domain.co.uk:80 [Mon Feb 04 11:06:54 2008] [debug] proxy_util.c(1908): proxy: connected /public/jobs/admin/index.asp to backend.domain.co.uk:80 [Mon Feb 04 11:06:54 2008] [debug] proxy_util.c(2098): proxy: HTTP: connection complete to 192.168.1.2:80 (backend.domain.co.uk) [Mon Feb 04 11:06:54 2008] [info] [client 192.168.1.2] (32)Broken pipe: core_output_filter: writing data to the network [Mon Feb 04 11:06:54 2008] [error] [client 192.168.1.1] proxy: error reading status line from remote server backend.domain.co.uk, referer: http://admin.domain.co.uk/jobs/updated.asp [Mon Feb 04 11:06:54 2008] [error] [client 192.168.1.1] proxy: Error reading from remote server returned by /jobs/index.asp, referer: http://admin.domain.co.uk/jobs/updated.asp [Mon Feb 04 11:06:54 2008] [debug] proxy_util.c(1773): proxy: HTTP: has released connection for (backend.domain.co.uk) It seems to imply that the connection to the backend server failed although no packets are ever sent to that server! The packet capture shows that the 502 is returned to the client 434 micro-seconds after the ldap call returned a success! I have another virtual host configured on the same server, with an almost identical configuration except that it has no authentication configured. This site has procesed thousands of requests this morning and not one error! Whereas the troublesome site has returned 35 errors out of 443 requests! Going directly to the backend server works all the time! One other difference that I've just thought of with this backend server is that it has two IP addresses (for historical reasons). Is that known to cause any problems? I'm currently running CentOS 5 with Apache 2.2.3 (including all the patches that RedHat have backported). Any advice on this problem would be very much appreciated. Many thanks in advance, Neil. -- Neil Hillard neil.hillard@xxxxxxxxxxxxxxxxxx AgustaWestland http://www.whl.co.uk/ Disclaimer: This message does not necessarily reflect the views of Westland Helicopters Ltd. --------------------------------------------------------------------- The official User-To-User support forum of the Apache HTTP Server Project. See <URL:http://httpd.apache.org/userslist.html> for more info. To unsubscribe, e-mail: users-unsubscribe@xxxxxxxxxxxxxxxx " from the digest: users-digest-unsubscribe@xxxxxxxxxxxxxxxx For additional commands, e-mail: users-help@xxxxxxxxxxxxxxxx