在我们的从属 NIS 服务器上，/etc/sysconfig/network我已经设置了
YPSERV_ARGS="-p 944"
YPXFRD_ARGS="-p 945"
以及OTHER_YPBIND_OPTS="-p 3000"在/etc/ypbind.conf以及YPPASSWDD_ARGS="--port 946"在 /etc/sysconfig/yppasswdd
但在主服务器上，当运行make -C /var/yp并启用防火墙调试时，目标端口 (DPT) 总是会改变。它始终是 UDP。
kernel: FINAL_REJECT: IN=eno3 OUT= MAC=00:0a:f7:e1:f8:6c:00:0a:f7:e1:d3:71:08:00 SRC=nis-slave DST=nis-master LEN=76 TOS=0x00 PREC=0x00 TTL=64 ID=59404 DF PROTO=UDP SPT=1003 DPT=676 LEN=56
此外，/etc/nfs.conf我们还推出了：
[lockd]
port=4002
udp-port=4002
[mountd]
port=4003
[nfsd]
port=2049
port=4001
outgoing-port=4004
从服务器中的日志显示：ypxfr_callback call: RPC: Unable to receive; errno = No route to host
停止防火墙，一切正常。那么什么服务在使用 UDP？
答案1
古老的 YP/NIS 根本不适合防火墙。它实际上早于主机防火墙的广泛使用。正如您所注意到的，它期望能够在任意端口上进行通信。过去 20 年左右的大多数协议不再这样做，而是在可预测（或至少可配置）的端口上运行。
但是，作为一种解决方法，如果您只有一个 IP 地址，您可以将其添加到trusted防火墙中的区域，这样来自该 IP 地址的所有流量都将被允许。（来源也可以通过 CIDR 范围或 MAC 地址提供。）
firewall-cmd --zone=trusted --add-source=10.193.35.1 [--permanent]
答案2
同意 NIS 已经过时了，如无必要就不要使用它。
为了NFS以下是我从 SLES 11.4 中获取的示例。/etc/sysconfig/nfs
请注意，根据您使用的 NFS 版本和 Linux 发行版，情况可能会略有不同。但您需要在防火墙中打开的端口号至少为MOUNTD_PORT和SM_NOTIFY_OPTIONS和STATD_PORT和LOCKD_TCPPORT以及LOCKD_UDPPORTNFS 服务的端口号（对于 TCP 和 UDP，通常为 111 和 2049）。
因为custom_number_1要custom_number_4使用 1024 以上的值，任何低于 1024 的值都是为特权服务保留。显然，您不想选择与其他服务冲突的数字，您可以使用 1024..9999 的范围，但根据个人喜好，我将我的设置为 10,000 以上。范围 >= 49152 是相信动态范围我不认为你应该选择它；如果你不配置 NFS（告诉它使用什么），那么它会动态选择它们，并且它会是一些 >= 49152 的端口号，并且每次都会有所不同，因为它是动态的...以及为什么您会遇到问题，因为防火墙会阻止所有这些端口，并且您永远不会知道它们是什么，因为 NFS 会动态选择它们。
您为 NIS 描述的动态选择端口号，同样的情况；服务未完全配置，因此留空或默认或动态选择的内容=每次都不同=无法正确配置或使用防火墙。
## Path: Network/File systems/NFS server
## Description: number of threads for kernel nfs server
## Type: integer
## Default: 4
## ServiceRestart: nfsserver
#
# the kernel nfs-server supports multiple server threads
#
USE_KERNEL_NFSD_NUMBER="4"
## Path: Network/File systems/NFS server
## Description: use fixed port number for mountd
## Type: integer
## Default: ""
## ServiceRestart: nfsserver
#
# Only set this if you want to start mountd on a fixed
# port instead of the port assigned by rpc. Only for use
# to export nfs-filesystems through firewalls.
#
MOUNTD_PORT="custom_number_1"
## Path: Network/File systems/NFS server
## Description: GSS security for NFS
## Type: yesno
## Default: yes
## ServiceRestart: nfs nfsserver
#
# Enable RPCSEC_GSS security for NFS (yes/no)
#
NFS_SECURITY_GSS="no"
## Path: Network/File systems/NFS server
## Description: NFSv4 protocol support
## Type: yesno
## Default: yes
## ServiceRestart: nfs nfsserver
#
# Enable NFSv4 support (yes/no)
#
NFS4_SUPPORT="no"
## Path: Network/File systems/NFS server
## Description: NFSv4 server minor version
## Type: integer
## Default: 0
## ServiceRestart: nfsserver
#
# Select NFSv4 minor version for server to support (0, 1).
# If '1' is selected, both NFSv4.0 and NFSv4.1 will be supported.
NFS4_SERVER_MINOR_VERSION="0"
## Path: Network/File systems/NFS server
## Description: Network Status Monitor options
## Type: string
## Default: ""
#
# If a fixed port should be used to send reboot notification
# messages to other systems, that port should be given
# here as "-p portnumber".
#
SM_NOTIFY_OPTIONS="-p custom_number_2"
## Path: Network/File systems/NFS server
## Description: Always start NFS services
## Type: yesno
## Default: no
## ServiceRestart nfs
#
# Always start NFS services (gssd, idmapd), not only if
# there are nfs mounts in /etc/fstab. This is likely to be
# needed if you use an automounter for NFS.
#
NFS_START_SERVICES=""
## Path: Network/File systems/NFS server
## Description: Port rpc.statd should listen on
## Type: integer
## Default: ""
## ServiceRestart: nfsserver
#
# Statd will normally choose a random port to listen on and
# SuSE-Firewall is able to detect which port and allow for it.
# If you have another firewall, you may want to set a fixed
# port number which can then be opened in that firewall.
STATD_PORT="custom_number_3"
## Path: Network/File systems/NFS server
## Description: Hostname used by rpc.statd
## Type: string
## Default: ""
## ServiceRestart: nfsserver
#
# statd will normally use the system hostname in status
# monitoring conversations with other hosts. If a different
# host name should be used, as can be useful with fail-over
# configurations, that name should be given here.
#
STATD_HOSTNAME=""
## Path: Network/File systems/NFS server
## Description: TCP Port that lockd should listen on
## Type: integer
## Default: ""
## ServiceRestart: nfsserver
#
# Lockd will normally choose a random port to listen on and
# SuSE-Firewall is able to detect which port and allow for it.
# If you have another firewall, you may want to set a fixed
# port number which can then be opened in that firewall.
# lockd opens a UDP and a TCP port. This setting only affect
# the TCP port.
LOCKD_TCPPORT="custom_number_4"
## Path: Network/File systems/NFS server
## Description: UDP Port that lockd should listen on
## Type: integer
## Default: ""
## ServiceRestart: nfsserver
#
# Lockd will normally choose a random port to listen on and
# SuSE-Firewall is able to detect which port and allow for it.
# If you have another firewall, you may want to set a fixed
# port number which can then be opened in that firewall.
# lockd opens a UDP and a TCP port. This setting only affect
# the UDP port.
LOCKD_UDPPORT="custom_number_4"
## Path: Network/File systems/NFS server
## Description: Lease time for NFSv4 leases
## Type: integer
## Default: ""
#
# Set the lease time for the NFSv4 server. This allows new locks
# to be taken sooner after a server restart, so it is useful for
# servers which need to recover quickly after a failure, particularly
# in fail-over configurations. Reducing the lease time can be a
# problem is some clients connect over high latency networks.
# The default is 90 seconds. A number like 15 might be appropriate
# in a fail-over configuration with all clients on well connected
# low latency links.
NFSV4LEASETIME=""
## Path: Network/File systems/NFS server
## Description: Alternate mount point for rpc_pipefs filesystem
## Type: string
## Default: ""
#
# In a high-availabilty configuration it is possible that /var/lib/nfs
# is redirected so some shared storage and so it is not convenient to
# mount the rpc_pipefs filesystem at /var/lib/nfs/rpc_pipefs. In that
# case an alternate mount point can be given here.
RPC_PIPEFS_DIR=""
## Path: Network/File systems/NFS server
## Description: Options for svcgssd
## Type: string
## Default: ""
#
# Normally svcgssd does not require any option. However in a
# high-availabilty configuration it can be useful to pass "-n"
# to guide the choice of default credential. To allow for that
# case or any other requiring options ot svcgssd, they can
# be specified here.
SVCGSSD_OPTIONS=""
## Path: Network/File systems/NFS server
## Description: Extra options for nfsd
## Type: string
## Default: ""
#
# This setting allows extra options to be specified for NFSD, such as
# -H <shared_hostname> in a high-availability configuration.
NFSD_OPTIONS=""
## Path: Network/File systems/NFS server
## Description: Extra options for gssd
## Type: string
## Default: ""
#
# Normally gssd does not require any options. In some circumstances,
# -n, -l or other options might be useful. See "man 8 rpc.gssd" for
# details. Those options can be set here.
GSSD_OPTIONS=""
## Path: Network/File systems/NFS server
## Description: Extra options for mountd
## Type: string
## Default: ""
#
# Normally mountd does not require any options. In some circumstances,
# -n, -t, -g or other options might be useful. See "man 8 rpc.mountd" for
# details. Those options can be set here.
# -p or -N should be set using MOUNTD_PORT or NFS4_SUPPORT rather than
# this option.
MOUNTD_OPTIONS=""
## Path: Network/File systems/NFS server
## Description: Avoid DNS lookups for kerberos principal
## Type: yesno
## Default: no
## ServiceRestart: gssd
#
# Avoid DNS lookups when determining kerberos identity
# of NFS server (yes/no)
# "yes" is safest, but "no" might be needed to preserve
# correct behaviour at sites that don't use
# Fully Qualified Domain Names when mounting NFS Shares.
#
NFS_GSSD_AVOID_DNS="no"