UNIX for Advanced & Expert Users

Hi,
This is my first post to this site. So kindly forgive if I am writing in a wrong section.
My query is that...
I want to modify the max username length size. I guess it is 32/64 on CentOS. Now I want to change it to 128. Is there any way to do that?
Thanks in advance!!

From the command line try:

Code:

getconf _POSIX_LOGIN_NAME_MAX  
#or 
getconf LOGIN_NAME_MAX

For a lot of reasons it is a really, really bad idea to try to exceed this value:
applications using (_POSIX_)LOGIN_NAME_MAX for usernames will segfault.
LDAP will not work.
Other PAM schemes will not work.
OpenSSH protocol 1 will fail with overlong usernames.
/etc/rhosts won't work for users on your box connecting to remote boxes

I don't think anything good will come from this but try editing /etc/default/login.defs.
CentOS follows Red Hat useradd conventions, see: /etc/default/useradd

Thanks a lot for ur reply, Jim
And, how can I increase the login name character limit in ftp?
Coz, I have noticed that when I use long login name(more than 20 character) to login using ftp command, it rejects my request.
I m very new to Unix. So please kindly tolerate my stupid questions

One way is to switch to using VSFTP. In the RHEL4 vsftpd package, the maximum username length was been increased to 128. For a while it dropped back to 32 characters (RHEL5 vsftpd-2.0.5-12.el5) but the regression was subsequently fixed.

Thanks