When mounting NFS, You need to activate the access permissions for those ports.

When mounting NFS, You need to activate the access permissions for those ports.

Mount 10.12.13.11:/vol/lft_jjmk/mnt
Unable to mount, because the network has a limited permission configuration, in order to find out which ports need to be activated to mount nfs, the following attempt is made here.
After you have knocked on the command, you are in the waiting status.Mount 10.12.13.11:/vol/lft_jjmk/mnt
Open another window at the same time. Run netstat-[Root @ LFTt-test02 ~] # Netstat-an "grep 10.12.13.11tcp 0 1 10.12.4.24: 34122 10.12.13.11: 11 SYN_SENT
Tcp 0 1 10.12.4.24: 717 10.12.13.11: 2049 SYN_SENT
Udp 0 0 10.12.4.24: 37291 10.12.13.11: * ESTABLISHED
As you can seeTcp 111 and 2049In addition, there is another 10.12.13.11: * regardless of whether the two ports are enabled, the two ports still cannot be connected.

By capturing packets through tcpdump, 111 2049 and a udp connection acp-proto port will be called when the local machine is mounted to nfs.Command: tcpdump-I eht0 dst host 10.12.13.11
Packet Capture found that udp is required to connect to the acp-proto port, and then it is found to be port 4046.

At this point, I am looking for A network colleague to add network permissions. port 111 2049 4046 has the permission to give this server A access to 10.12.13.11 and the result still cannot be connected.
Continue
Then I found a server that can be mounted normally. I caught it and found that the Mount operation involved the nfs tcp 2049 ports, which is obviously everywhere.
Sunrpctcp 111, which is obviously everywhere
Sunrpcudp 111, which is hard to find. It can be seen only after careful troubleshooting.
Acp-protoudp 4046, which will be found after a careful look at udp

Then, configure the permission to access the four ports 10.12.13.11 and try again to mount them normally. Tcp 111 2049 port udp 111 4046 Port
The following is the packet capture process of a tcpdump mounted to nfs.Tcpdump-I eht0 dst host 10.12.13.1113:14:42. 208825 IP 172.16.4.134.818> 10.12.13.11.nfs: Flags [S], seq 3321839051, win 14600, options [mss 1460, sackOK, TS val 3321390887 ecr 0, nop, wscale 7], length 0
13:14:42. 210567 IP 172.16.4.134.818> 10.12.13.11.nfs: Flags [.], ack 3365250555, win 115, options [nop, nop, TS val 3321390889 ecr 298615938], length 0
13:14:42. 210626 IP 172.16.4.134.1152395164> 10.12.13.11.2049: 40 null
13:14:42. 212157 IP 172.16.4.134.818> 10.12.13.11.nfs: Flags [.], ack 37, win 115, options [nop, nop, TS val 3321390890 ecr 298615940], length 0
13:14:42. 212236 IP 172.16.4.134.818> 10.12.13.11.nfs: Flags [F.], seq 44, ack 37, win 115, options [nop, nop, TS val 3321390890 ecr 298615940], length 0
13:14:42. 213883 IP 172.16.4.134.818> 10.12.13.11.nfs: Flags [.], ack 38, win 115, options [nop, nop, TS val 3321390892 ecr 298615941], length 0
13:14:42. 220327 IP 172.16.4.134.48913> 10.12.13.11.sunrpc: Flags [S], seq 4275201135, win 14600, options [mss 1460, sackOK, TS val 3321390899 ecr 0, nop, wscale 7], length 0
13:14:42. 222117 IP 172.16.4.134.48913> 10.12.13.11.sunrpc: Flags [.], ack 2204017511, win 115, options [nop, nop, TS val 3321390900 ecr 298615949], length 0
13:14:42. 228992 IP 172.16.4.134.48913> 10.12.13.11.sunrpc: Flags [P.], seq 0: 60, ack 1, win 115, options [nop, nop, TS val 3321390907 ecr 298615949], length 60
13:14:42. 230805 IP 172.16.4.134.48913> 10.12.13.11.sunrpc: Flags [.], ack 33, win 115, options [nop, nop, TS val 3321390909 ecr 298615958], length 0
13:14:42. 230868 IP 172.16.4.134.48913> 10.12.13.11.sunrpc: Flags [F.], seq 60, ack 33, win 115, options [nop, nop, TS val 3321390909 ecr 298615958], length 0
13:14:42. 230930 IP 172.16.4.134.53578> 10.12.13.11.nfs: Flags [S], seq 3487179920, win 14600, options [mss 1460, sackOK, TS val 3321390909 ecr 0, nop, wscale 7], length 0
13:14:42. 232507 IP 172.16.4.134.48913> 10.12.13.11.sunrpc: Flags [.], ack 34, win 115, options [nop, nop, TS val 3321390911 ecr 298615960], length 0
13:14:42. 232658 IP 172.16.4.134.53578> 10.12.13.11.nfs: Flags [.], ack 3914232987, win 115, options [nop, nop, TS val 3321390911 ecr 298615960], length 0
13:14:42. 232731 IP 172.16.4.134.3326872918> 10.12.13.11.2049: 40 null
13:14:42. 234326 IP 172.16.4.134.53578> 10.12.13.11.nfs: Flags [.], ack 29, win 115, options [nop, nop, TS val 3321390913 ecr 298615962], length 0
13:14:42. 234387 IP 172.16.4.134.53578> 10.12.13.11.nfs: Flags [F.], seq 44, ack 29, win 115, options [nop, nop, TS val 3321390913 ecr 298615962], length 0
13:14:42. 234554 IP 172.16.4.134.41320>10.12.13.11.sunrpc: UDP, Length 56
13:14:42. 236058 IP 172.16.4.134.53578> 10.12.13.11.nfs: Flags [.], ack 30, win 115, options [nop, nop, TS val 3321390914 ecr 298615963], length 0
13:14:42. 236356 IP 172.16.4.134.33212>10.12.13.11.acp-proto: UDP, Length 40
13:14:42. 238234 IP 172.16.4.134.944>10.12.13.11.acp-proto: UDP, Length 40
13:14:42. 240047 IP 172.16.4.134.944>10.12.13.11.acp-proto: UDP, Length 88
13:14:42. 241996 IP 172.16.4.134.59597> 10.12.13.11.sunrpc: Flags [S], seq 525024676, win 14600, options [mss 1460, sackOK, TS val 3321390920 ecr 0, nop, wscale 7], length 0
13:14:42. 243782 IP 172.16.4.134.59597> 10.12.13.11.sunrpc: Flags [.], ack 2351267448, win 115, options [nop, nop, TS val 3321390922 ecr 298615971], length 0
13:14:42. 243809 IP 172.16.4.134.59597> 10.12.13.11.sunrpc: Flags [P.], seq 0: 88, ack 1, win 115, options [nop, nop, TS val 3321390922 ecr 298615971], length 88
13:14:42. 245561 IP 172.16.4.134.59597> 10.12.13.11.sunrpc: Flags [.], ack 33, win 115, options [nop, nop, TS val 3321390924 ecr 298615973], length 0
13:14:42. 245592 IP 172.16.4.134.59597> 10.12.13.11.sunrpc: Flags [F.], seq 88, ack 33, win 115, options [nop, nop, TS val 3321390924 ecr 298615973], length 0
13:14:42. 245646 IP 172.16.4.134.846> 10.12.13.11.nfs: Flags [S], seq 1850298836, win 14600, options [mss 1460, sackOK, TS val 3321390924 ecr 0, nop, wscale 7], length 0
13:14:42. 247281 IP 172.16.4.134.59597> 10.12.13.11.sunrpc: Flags [.], ack 34, win 115, options [nop, nop, TS val 3321390926 ecr 298615975], length 0
13:14:42. 247581 IP 172.16.4.134.846> 10.12.13.11.nfs: Flags [.], ack 2793687147, win 115, options [nop, nop, TS val 3321390926 ecr 298615975], length 0
13:14:42. 247634 IP 172.16.4.134.822659610> 10.12.13.11.2049: 40 null
13:14:42. 249445 IP 172.16.4.134.846> 10.12.13.11.nfs: Flags [.], ack 29, win 115, options [nop, nop, TS val 3321390928 ecr 298615977], length 0
13:14:42. 250671 IP 172.16.4.134.839410426> 10.12.13.11.2049: 40 null
13:14:42. 252384 IP 172.16.4.134.856214042> 10.12.13.11.2049: 108 fsinfo fh 1073741824/
13:14:42. 254330 IP 172.16.4.134.872991258> 10.12.13.11.2049: 108 pathconf fh 1073741824, 64/
13:14:42. 256247 IP 172.16.4.134.889768474> 10.12.13.11.2049: 108 fsinfo fh 1073741824/
13:14:42. 297329 IP 172.16.4.134.846> 10.12.13.11.nfs: Flags [.], ack 537, win 140, options [nop, nop, TS val 3321390976 ecr 298615985], length 0

Other useful tcpdump commands

[Root @ monitor ~] # Tcpdump tcp port 111 and dst host 10.12.13.11-n
Tcpdump: verbose output suppressed, use-v or-vv for full protocol decode
Listening on eth1, link-type EN10MB (Ethernet), capture size 65535 bytes
13:32:30. 070052 IP 172.16.4.134.55618> 10.12.13.11.sunrpc: Flags [S], seq 3437328233, win 14600, options [mss 1460, sackOK, TS val 3322458748 ecr 0, nop, wscale 7], length 0
13:32:30. 071842 IP 172.16.4.134.55618> 10.12.13.11.sunrpc: Flags [.], ack 1251460408, win 115, options [nop, nop, TS val 3322458750 ecr 299683835], length 0
13:32:30. 073784 IP 172.16.4.134.55618> 10.12.13.11.sunrpc: Flags [P.], seq 0: 60, ack 1, win 115, options [nop, nop, TS val 3322458752 ecr 299683835], length 60
13:32:30. 075537 IP 172.16.4.134.55618> 10.12.13.11.sunrpc: Flags [.], ack 33, win 115, options [nop, nop, TS val 3322458754 ecr 299683839], length 0
13:32:30. 075618 IP 172.16.4.134.55618> 10.12.13.11.sunrpc: Flags [F.], seq 60, ack 33, win 115, options [nop, nop, TS val 3322458754 ecr 299683839], length 0
13:32:30. 077275 IP 172.16.4.134.55618> 10.12.13.11.sunrpc: Flags [.], ack 34, win 115, options [nop, nop, TS val 3322458755 ecr 299683841], length 0
13:32:30. 087082 IP 172.16.4.134.44143> 10.12.13.11.sunrpc: Flags [S], seq 2174267455, win 14600, options [mss 1460, sackOK, TS val 3322458765 ecr 0, nop, wscale 7], length 0
13:32:30. 088851 IP 172.16.4.134.44143> 10.12.13.11.sunrpc: Flags [.], ack 3403567045, win 115, options [nop, nop, TS val 3322458767 ecr 299683852], length 0
13:32:30. 088893 IP 172.16.4.134.44143> 10.12.13.11.sunrpc: Flags [P.], seq 0: 88, ack 1, win 115, options [nop, nop, TS val 3322458767 ecr 299683852], length 88
13:32:30. 090598 IP 172.16.4.134.44143> 10.12.13.11.sunrpc: Flags [.], ack 33, win 115, options [nop, nop, TS val 3322458769 ecr 299683854], length 0
13:32:30. 090637 IP 172.16.4.134.44143> 10.12.13.11.sunrpc: Flags [F.], seq 88, ack 33, win 115, options [nop, nop, TS val 3322458769 ecr 299683854], length 0
13:32:30. 092522 IP 172.16.4.134.44143> 10.12.13.11.sunrpc: Flags [.], ack 34, win 115, options [nop, nop, TS val 3322458771 ecr 299683856], length 0

Tcpdump-I eht0 udp port 111 and dst host 10.12.13.11
13:21:29. 656365 IP 172.16.4.134.20.5> 10.12.13.11.sunrpc: UDP, length 56

Then, configure the permission to access the four ports 10.12.13.11 and try again to mount them normally. Tcp 111 2049 port udp 111 4046 Port