Red Hat Bugzilla – Bug 6642
ypbind failes to bind to NIS Master Server if DNS lookups are not possible
Last modified: 2008-05-01 11:37:52 EDT
Hi folks, while setting up a NIS Master server on RH6.1 i noticed the following problem: OS: RedHat 6.1 (out of the box, no patches installed) PC: i686,128MB SDRAM, MB: Abit dual Celeron (currently only 1 CPU) SCSI: AHA2940U2W NIC: 3c905B TX Purpose of this host: It's my internal NIS Master server and NFS Server for RH 6.1 clients. Later (if everything is setup) it will become also my primary caching only DNS server (non authoritative). But for now i did *not* setup DNS, since i use the external DNS Server of my ISP. I guess this causes the problem. Please read on. I connect my internal network via a CISCO ISDN router to the internet. During installation/setup i always turn of my CISCO, to prevent insecure broadcasts/packets sent out to the Internet. I noticed that ypbind is not able to find my NIS Master server if it can not reach the Internet via my CISCO (guess it was trying to do a DNS lookup ???). Every host search path (nsswitch.conf, hosts.conf ...) specifyes dns to be the last entry. I use this order "files nis dns" ypbind is able to bind to my NIS master *only* if access to the Internet is possble (CISCO must be running). Does ypbind need a DNS lookup to resolve the NIS master, even if it's specified in /etc/hosts ??? I will further track down the problem when i have some spare time, but for now i guess it's because ypbind tries to resolve some names via DNS. Please tell me if i'm completely wrong, or if this is possible (Do i need an internal DNS server???) If it's possible, it might be a security problem, since ypbind requests must not be seen on the internet. Many thanks Thomas P.S.: RedHat 6.1 is a wonderfull distribution, keep up the good work!
I thibnk it is the ypserv which is confused about who he really is. tis usually happens when you alias the hostname of the NIS server to 127.0.0.1 in /etc/hosts.