Odd hangs with RT 3.0.11 with DNS

I have some odd hangs in my RT since some weeks and now I maybe figured
out what the cause could be.
RT is working fine but in some stage it stops for a specific client
(only saying “Loading” whatever I do.
Even waiting some minutes, the only way to recover is close/reopen the
browser - quite annoying…

  • It only happens on clients without reverse IP address resolution
  • I’d tend to say it happens when I click something (like Links) before
    a Ticket/Listing is completely loaded

now, looking on /server-status there’re the processes of this client
listed with “Mode of operation: D” which means DNS lookup and stay there
quite for a while… in my httpd.conf I have “HostnameLookups Off” so why
does apache even every do “DNS” ?
now for these specific clients it’d be probably easy to fix this by
making making reverse-lookup work but I cannot ensure reverese-lookup
for “outside” clients always,
anybody with a hint ? or is there a way to kill these nonresponding
childs in apache in a timely fashion ?
I’ve already set Maxrequestsperchild to 100 as advised here but this
doesn’t help for this problem…

running RT 3.0.11 from debian-package on Debian Sarge,Apache/1.3.31 some
of my httpd.conf parameters that might be relevant:
KeepAlive On
Timeout 300
MaxKeepAliveRequests 100
KeepAliveTimeout 15
MinSpareServers 5
MaxSpareServers 10
StartServers 5
MaxRequestsPerChild 100