I've turned Network Manager off and wanted to bring up eth0 manually. 

# ifup eth0
Determining IP information for eth0.../etc/sysconfig/network-scripts/ifup-eth: line 290: 10371 Segmentation fault      /sbin/dhclient ${DHCLIENTARGS} ${DEVICE}
 failed.

initscripts-8.89-1.i386
selinux-policy-3.6.6-1.fc11.noarch

This happens only if selinux is in enforcing mode, permissive passes. Log:
node=kovy.englab.brq.redhat.com type=AVC msg=audit(1234964955.23:58): avc: denied { search } for pid=3838 comm="dhclient-script" name="network-scripts" dev=dm-0 ino=442372scontext=unconfined_u:system_r:dhcpc_t:s0 tcontext=system_u:object_r:net_conf_t:s0 tclass=dir

node=kovy.englab.brq.redhat.com type=SYSCALL msg=audit(1234964955.23:58): arch=40000003 syscall=195 success=no exit=-13 a0=871de28 a1=bff0cdcc a2=7f7ff4 a3=871de2a items=0ppid=3827 pid=3838 auid=500 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=1 comm="dhclient-script" exe="/bin/bash" subj=unconfined_u:system_r:dhcpc_t:s0 key=(null)