Not able to access Webmin remotely for awhile

Webmin
61 
$ sudo nmap 62.171.154.199
[sudo] password for joe: 
Starting Nmap 7.93 ( https://nmap.org ) at 2023-05-06 12:54 CDT
Nmap scan report for vmi495036.contaboserver.net (62.171.154.199)
Host is up (0.16s latency).
Not shown: 990 filtered tcp ports (no-response)
PORT    STATE  SERVICE
22/tcp  open   ssh
25/tcp  open   smtp
80/tcp  open   http
110/tcp closed pop3
143/tcp closed imap
443/tcp open   https
465/tcp open   smtps
587/tcp open   submission
993/tcp closed imaps
995/tcp closed pop3s

Nmap done: 1 IP address (1 host up) scanned in 10.35 seconds

Something at the network layer is not allowing port 10000.

Compre to, e.g., one of my systems:

$ sudo nmap www.virtualmin.com 
Starting Nmap 7.93 ( https://nmap.org ) at 2023-05-06 12:55 CDT
Nmap scan report for www.virtualmin.com (45.76.57.243)
Host is up (0.028s latency).
Not shown: 847 closed tcp ports (reset), 135 filtered tcp ports (no-response), 7 filtered tcp ports (admin-prohibited)
PORT      STATE SERVICE
21/tcp    open  ftp
22/tcp    open  ssh
25/tcp    open  smtp
53/tcp    open  domain
80/tcp    open  http
443/tcp   open  https
465/tcp   open  smtps
587/tcp   open  submission
2222/tcp  open  EtherNetIP-1
3306/tcp  open  mysql
10000/tcp open  snet-sensor-mgmt

Nmap done: 1 IP address (1 host up) scanned in 1.92 seconds
62

I went through everything. Didn’t work.

63

iptables.txt was blank

64

I tried different ports. None of them worked.

65

Contabo is pretty budget. Doubt they even offer load balancing.

66

I don’t recall you ever saying you checked for OOM killer errors in the kernel log (dmesg).

67

This really says that you are not reaching the system, so DNS or firewall, even TCP wrappers - hosts.allow

68

Here.
dmesg.zip (16.3 KB)

69

Hello. Please post here output from lsmod | egrep ‘net|filter|table|nft|ipt|bpf’

70

What’s the command you want me to run?

71

It listing loaded module in your kernel. net are networking modules, filter is a packet filter module usage and ipt, nft, and bpf is types of packet filters. From your dmesg I think you have a BPF packet filter used in the kernel. I want to make sure about it, because it is also a firewall. I see that you enjoy the virtual machine kvm. What frontend are you using? Or your provider. Proxmox? In proxmox kernel images is BPFILTER is often allowed and in installation used.

72

Did you want me to run a command?

73

Yes, as root. Command is:
lsmod | egrep ‘net|filter|table|nft|ipt|bpf’

74

nft: no command specified

Command ‘table’ not found, but can be installed with:

snap install table

Command ‘filter’ not found, but can be installed with:

apt install filter

Command ‘bpf’’ not found, did you mean:

command ‘bpfc’ from deb netsniff-ng (0.6.5-1build1)

Try: apt install

Command ‘ipt’ not found, did you mean:

command ‘opt’ from deb llvm (1:10.0-50~exp1)
command ‘pt’ from deb tcllib (1.20+dfsg-1)
command ‘idt’ from deb ncl-ncarg (6.6.2-1build4)
command ‘iptc’ from deb libiptcdata-bin (1.0.5-2.1ubuntu4)
command ‘apt’ from deb apt (2.0.9)
command ‘dpt’ from deb pkg-perl-tools (0.59)
command ‘ipa’ from deb freeipa-client (4.8.6-1ubuntu2)
command ‘ppt’ from deb bsdgames (2.17-28build1)
command ‘iyt’ from deb python3-yt (3.5.1-3build1)
command ‘ips’ from deb ips (4.0-1build3)
command ‘ipbt’ from deb its-playback-time (0.2017-08-30.3c40fd3-1)
command ‘ip’ from deb iproute2 (5.5.0-1ubuntu1)
command ‘iat’ from deb iat (0.1.3-7build1)
command ‘gpt’ from deb gpt (1.1-5build1)
command ‘ipe’ from deb ipe (7.2.13-2build1)

75

No, you started it incorrectly. Do not install anything. They are two statements concatenated by a pipe. lsmod and egrep and “|” a pipe between them. lsmod list all modules and egrep select just expected.

76

I copy and pasted exactly what you asked:
root@k9sports:/# lsmod | egrep ‘net|filter|table|nft|ipt|bpf’

77

Here is my output if I’am standard user:
ony@ares:~$ lsmod | egrep ‘net|filter|table|nft|ipt|bpf’
Command ‘nft’ is available in the following places

  • /sbin/nft
  • /usr/sbin/nft
    The command could not be located because ‘/sbin:/usr/sbin’ is not included in the PATH environment variable.
    This is most likely caused by the lack of administrative privileges associated with your user account.
    nft: command not found
    Command ‘bpf’’ not found, did you mean:
    command ‘bpfc’ from deb netsniff-ng
    Try: sudo apt install
    Command ‘table’ not found, but can be installed with:
    sudo snap install table
    Command ‘filter’ not found, but can be installed with:
    sudo apt install filter
    Command ‘ipt’ not found, did you mean:
    command ‘gpt’ from deb gpt
    command ‘iat’ from deb iat
    command ‘iyt’ from deb python3-yt
    command ‘ips’ from deb ips
    command ‘ip’ from deb iproute2
    command ‘idt’ from deb ncl-ncarg
    command ‘opt’ from deb llvm
    command ‘ipa’ from deb freeipa-client
    command ‘ipe’ from deb ipe
    command ‘apt’ from deb apt
    command ‘iptc’ from deb libiptcdata-bin
    command ‘ipbt’ from deb its-playback-time
    command ‘dpt’ from deb pkg-perl-tools
    command ‘pt’ from deb tcllib
    Try: sudo apt install

but I’am s root output is:

root@ares:~# lsmod | egrep ‘net|filter|table|nft|ipt|bpf’
usbnet 57344 2 rndis_host,cdc_ether
mii 16384 1 usbnet
nft_objref 16384 1
nf_conntrack_netbios_ns 16384 1
nf_conntrack_broadcast 16384 1 nf_conntrack_netbios_ns
nft_fib_inet 16384 1
nft_fib_ipv4 16384 1 nft_fib_inet
nft_fib_ipv6 16384 1 nft_fib_inet
nft_fib 16384 3 nft_fib_ipv6,nft_fib_ipv4,nft_fib_inet
nft_reject_inet 16384 8
nf_reject_ipv4 16384 1 nft_reject_inet
nf_reject_ipv6 20480 1 nft_reject_inet
nft_reject 16384 1 nft_reject_inet
nft_ct 24576 8
nft_chain_nat 16384 3
nf_nat 57344 1 nft_chain_nat
nf_conntrack 188416 4 nf_nat,nft_ct,nf_conntrack_netbios_ns,nf_conntrack_broadcast
nf_tables 286720 305 nft_ct,nft_reject_inet,nft_fib_ipv6,nft_objref,nft_fib_ipv4,nft_chain_nat,nft_reject,nft_fib,nft_fib_inet
libcrc32c 16384 3 nf_conntrack,nf_nat,nf_tables
nfnetlink 20480 3 nf_tables,ip_set
ip_tables 36864 0
x_tables 61440 1 ip_tables
usbcore 344064 8 xhci_hcd,usbnet,usbhid,rndis_host,uvcvideo,btusb,xhci_pci,cdc_ether

Please use:
sudo lsmod | egrep ‘net|filter|table|nft|ipt|bpf’

78

Sure:

root@k9sports:/# sudo lsmod | egrep ‘net|filter|table|nft|ipt|bpf’
nft: no command specified

Command ‘table’ not found, but can be installed with:

snap install table

Command ‘ipt’ not found, did you mean:

command ‘dpt’ from deb pkg-perl-tools (0.59)
command ‘iyt’ from deb python3-yt (3.5.1-3build1)
command ‘ips’ from deb ips (4.0-1build3)
command ‘iptc’ from deb libiptcdata-bin (1.0.5-2.1ubuntu4)
command ‘gpt’ from deb gpt (1.1-5build1)
command ‘opt’ from deb llvm (1:10.0-50~exp1)
command ‘ip’ from deb iproute2 (5.5.0-1ubuntu1)
command ‘iat’ from deb iat (0.1.3-7build1)
command ‘ipa’ from deb freeipa-client (4.8.6-1ubuntu2)
command ‘ipbt’ from deb its-playback-time (0.2017-08-30.3c40fd3-1)
command ‘pt’ from deb tcllib (1.20+dfsg-1)
command ‘apt’ from deb apt (2.0.9)
command ‘ipe’ from deb ipe (7.2.13-2build1)
command ‘ppt’ from deb bsdgames (2.17-28build1)
command ‘idt’ from deb ncl-ncarg (6.6.2-1build4)

Try: apt install

Command ‘bpf’’ not found, did you mean:

command ‘bpfc’ from deb netsniff-ng (0.6.5-1build1)

Try: apt install

Command ‘filter’ not found, but can be installed with:

apt install filter

79

Or use: sudo su -
Test root account with command: whoami
Output from whoami must be: root
An after use command lsmod | egrep ‘net|filter|table|nft|ipt|bpf’

80

whoami is: root