Description of problem:

The ip address of the remote client was used as the map filename.

[2017/03/06 16:42:39.859984,  0] ../source3/modules/vfs_expand_msdfs.c:56(read_target_host)
  can't open IP map 10.100.0.204. Error No such file or directory


In the vfs_expand_mfs.c file, we could  see that the parameters are reversed in the function definition and function call.
See below.

targethost = read_target_host(
        ctx, raddr, mapfilename);


static char *read_target_host(TALLOC_CTX *ctx, const char *mapfile,
                  const char *clientaddr)

the patch is simple:

diff source3/modules/vfs_expand_msdfs.c ../samba-4.2.10/source3/modules/vfs_expand_msdfs.c
151c151
<               ctx, mapfilename, raddr);
---
>               ctx, raddr, mapfilename);


Version-Release number of selected component (if applicable):


[root@mediasrv01 samba]# rpm -qa | grep samba
samba-common-tools-4.2.10-6.2.el7_2.x86_64
samba-client-4.2.10-6.2.el7_2.x86_64
samba-common-libs-4.2.10-6.2.el7_2.x86_64
samba-common-4.2.10-6.2.el7_2.noarch
samba-vfs-evs-1.0.5-0.el7.x86_64
samba-client-libs-4.2.10-6.2.el7_2.x86_64
pcp-pmda-samba-3.10.6-2.el7.x86_64
samba-python-4.2.10-6.2.el7_2.x86_64
samba-4.2.10-6.2.el7_2.x86_64
samba-libs-4.2.10-6.2.el7_2.x86_64
[root@mediasrv01 samba]# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 7.2 (Maipo)

How reproducible:

Mount DFS share.


Actual results:

  can't open IP map 10.100.0.204. Error No such file or directory


Expected results:

 working share