上回说到设置共享文件夹需要关闭防火墙：
service iptables stop 或 systemctl stop firewalld
但是由于网络安全的问题，我们需要保持防火墙开启，如此便引入了新的问题：
打开防火墙后，会产生报错信息：
clnt_create: RPC: Port mapper failure - Unable to receive: errno 113 (No route to host)
rpc mount export: RPC: Unable to receive; errno = No route to host
该报错是因为我们将nfs的端口也禁用了，需要开启。
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找了很多办法，都比较乱，最终还是解决了。
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首先，查看端口情况
rpcinfo -p
program vers proto port service
100000 4 tcp 111 portmapper
100000 3 tcp 111 portmapper
100000 2 tcp 111 portmapper
100000 4 udp 111 portmapper
100000 3 udp 111 portmapper
100000 2 udp 111 portmapper
100024 1 udp 39351 status
100024 1 tcp 52381 status
100021 1 udp 51619 nlockmgr
100021 3 udp 51619 nlockmgr
100021 4 udp 51619 nlockmgr
打开防火墙，查看当前共享情况
showmount -e 192.168.
clnt_create: RPC: Port mapper failure - Unable to receive: errno 113 (No route to host)
编辑文档，加入如下信息（主要是打开portmapper、mountd、nfs三个端口）
/etc/sysconfig/iptables
-A INPUT -p tcp -m state --state NEW -m tcp --dport 2049 -j ACCEPT
-A INPUT -m state --state NEW -m udp -p udp --dport 2049 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 111 -j ACCEPT
-A INPUT -m state --state NEW -m udp -p udp --dport 111 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 20048 -j ACCEPT
-A INPUT -m state --state NEW -m udp -p udp --dport 20048 -j ACCEPT
若显示如下：则需安装iptables-services：（yum install iptables-services systemctl enable iptables.service）
iptables -L -n
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT udp -- 0.0.0.0/0 0.0.0.0/0 udp dpt:53
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:53
ACCEPT udp -- 0.0.0.0/0 0.0.0.0/0 udp dpt:67
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:67
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
INPUT_direct all -- 0.0.0.0/0 0.0.0.0/0
INPUT_ZONES_SOURCE all -- 0.0.0.0/0 0.0.0.0/0
INPUT_ZONES all -- 0.0.0.0/0 0.0.0.0/0
DROP all -- 0.0.0.0/0 0.0.0.0/0 ctstate INVALID
REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:2049
Chain FORWARD (policy ACCEPT)
target prot opt source destination
ACCEPT all -- 0.0.0.0/0 192.168.122.0/24 ctstate RELATED,ESTABLISHED
ACCEPT all -- 192.168.122.0/24 0.0.0.0/0
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable
REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
FORWARD_direct all -- 0.0.0.0/0 0.0.0.0/0
FORWARD_IN_ZONES_SOURCE all -- 0.0.0.0/0 0.0.0.0/0
FORWARD_IN_ZONES all -- 0.0.0.0/0 0.0.0.0/0
FORWARD_OUT_ZONES_SOURCE all -- 0.0.0.0/0 0.0.0.0/0
FORWARD_OUT_ZONES all -- 0.0.0.0/0 0.0.0.0/0
DROP all -- 0.0.0.0/0 0.0.0.0/0 ctstate INVALID
REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
ACCEPT udp -- 0.0.0.0/0 0.0.0.0/0 udp dpt:68
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
OUTPUT_direct all -- 0.0.0.0/0 0.0.0.0/0
Chain FORWARD_IN_ZONES (1 references)
target prot opt source destination
FWDI_public all -- 0.0.0.0/0 0.0.0.0/0 [goto]
FWDI_public all -- 0.0.0.0/0 0.0.0.0/0 [goto]
Chain FORWARD_IN_ZONES_SOURCE (1 references)
target prot opt source destination
Chain FORWARD_OUT_ZONES (1 references)
target prot opt source destination
FWDO_public all -- 0.0.0.0/0 0.0.0.0/0 [goto]
FWDO_public all -- 0.0.0.0/0 0.0.0.0/0 [goto]
Chain FORWARD_OUT_ZONES_SOURCE (1 references)
target prot opt source destination