Before reboot,
$ cat /etc/resolv.conf
; generated by /sbin/dhclient-script
nameserver 172.20.10.22
search mycomp.local myhost.com

After reboot, the search path in resolv.conf is overwritten by the hostname.
Please help to prevent this from occurring.
Thanks.
$ cat /etc/resolv.conf
; generated by /sbin/dhclient-script
nameserver 172.20.10.22
search penguin

What are the file-rights you got on resolv.conf? Maybe you wanna give us the rights of /etc/
/etc/resolv.conf

And with what user do you run the dhclient-script?

Read and understand the dhclient(8) manpages (and the complementary pages under the SEE ALSO section).

Or apply the brute force method:
# chattr +i /etc/resolv.conf

I create a /etc/dhclient.conf with 5 different values as follows, reboot 5 times, but still do not get my desired /etc/resolv.conf
request subnet-mask, broadcast-address, routers, domain-name, domain-name-servers, host-name, nis-domain;
request subnet-mask, broadcast-address, routers, domain-name, domain-name-servers, host-name, nis-domain, nis-servers;
request subnet-mask, broadcast-address, routers, domain-name, domain-name-servers, nis-domain, nis-servers;
request subnet-mask, broadcast-address, routers, domain-name, domain-name-servers, host-name, nis-domain;
request subnet-mask, broadcast-address, routers, domain-name, host-name, nis-domain, nis-servers;

The best I can get is:
$ cat /etc/resolv.conf
; generated by /sbin/dhclient-script
nameserver 172.20.10.22
search penguin