diff --git a/xCAT-client/xCAT-client.spec b/xCAT-client/xCAT-client.spec
index 31f856902..d3b9b2c3a 100644
--- a/xCAT-client/xCAT-client.spec
+++ b/xCAT-client/xCAT-client.spec
@@ -25,7 +25,7 @@ Requires: perl-xCAT >= %{epoch}:%(cat Version)
 
 # fping or nmap is needed by pping (in case xCAT-client is installed by itself on a remote client)
 %ifos linux
-Requires: nmap
+Requires: nmap perl-XML-Simple perl-XML-Parser
 %else
 Requires: expat 
 %endif
diff --git a/xCAT-server/xCAT-server.spec b/xCAT-server/xCAT-server.spec
index ca1637666..d43a5ad29 100644
--- a/xCAT-server/xCAT-server.spec
+++ b/xCAT-server/xCAT-server.spec
@@ -20,7 +20,7 @@ AutoReqProv: no
 # also need to fix Requires for AIX
 %ifos linux
 BuildArch: noarch
-Requires: perl-IO-Socket-SSL perl-XML-Simple
+Requires: perl-IO-Socket-SSL perl-XML-Simple perl-XML-Parser
 Obsoletes: atftp-xcat
 %endif
 
diff --git a/xCAT/xCAT.spec b/xCAT/xCAT.spec
index 5109229e9..1a7213a0f 100644
--- a/xCAT/xCAT.spec
+++ b/xCAT/xCAT.spec
@@ -24,7 +24,7 @@ Conflicts: xCATsn
 Requires: xCAT-server xCAT-client perl-DBD-SQLite
 
 %ifos linux
-Requires: httpd nfs-utils nmap bind perl-XML-Parser perl(CGI)
+Requires: httpd nfs-utils nmap bind perl(CGI)
 # On RHEL this pulls in dhcp, on SLES it pulls in dhcp-server
 Requires: /usr/sbin/dhcpd
 # On RHEL this pulls in openssh-server, on SLES it pulls in openssh
@@ -37,8 +37,6 @@ Requires: conserver-xcat yaboot-xcat
 %endif
 
 %ifarch i386 i586 i686 x86 x86_64
-# All versions of the nb rpms are pulled in so an x86 MN can manage nodes of any arch.
-# The nb rpms are used for dhcp-based discovery, and flashing, so for now we do not need them on a ppc MN.
 Requires: syslinux xCAT-genesis-x86_64 elilo-xcat
 Requires: ipmitool-xcat >= 1.8.9
 Requires: xnba-undi syslinux-xcat
diff --git a/xCATsn/xCATsn.spec b/xCATsn/xCATsn.spec
index d7271663b..4c688a374 100644
--- a/xCATsn/xCATsn.spec
+++ b/xCATsn/xCATsn.spec
@@ -15,27 +15,26 @@ Source1: xcat.conf
 Source2: license.tar.gz
 Source3: xCATSN 
 Provides: xCATsn = %{version}
-Requires: xCAT-server xCAT-client perl-xCAT perl-DBD-SQLite 
-
-%ifos linux
-Requires: perl-XML-Parser
-%endif
+Requires: xCAT-server xCAT-client perl-DBD-SQLite 
 
 Conflicts: xCAT
 
 %ifos linux
 # yaboot-xcat is pulled in so any SN can manage ppc nodes
-Requires: dhcp httpd nfs-utils nmap bind perl-XML-Parser
+Requires: httpd nfs-utils nmap bind
+# On RHEL this pulls in dhcp, on SLES it pulls in dhcp-server
+Requires: /usr/sbin/dhcpd
+# On RHEL this pulls in openssh-server, on SLES it pulls in openssh
+Requires: /usr/bin/ssh
 %ifnarch s390x
 Requires: /etc/xinetd.d/tftp
+# yaboot-xcat is pulled in so any MN can manage ppc nodes
 Requires: conserver-xcat yaboot-xcat 
 %endif
 %endif
 
 %ifarch i386 i586 i686 x86 x86_64
-# All versions of the nb rpms are pulled in so an x86 MN can manage nodes of any arch.
-# The nb rpms are used for dhcp-based discovery, and flashing, so for now we do not need them on a ppc MN.
-Requires: xCAT-nbroot-oss-x86 xCAT-nbroot-core-x86 xCAT-nbkernel-x86 xCAT-nbroot-oss-x86_64 xCAT-nbroot-core-x86_64 xCAT-nbkernel-x86_64 xCAT-nbroot-oss-ppc64 xCAT-nbroot-core-ppc64 xCAT-nbkernel-ppc64 syslinux
+Requires: syslinux xCAT-genesis-x86_64 elilo-xcat
 Requires: ipmitool-xcat >= 1.8.9
 Requires: xnba-undi syslinux-xcat
 %endif