My centos server has an iptables rule.
iptables -A INPUT -p tcp --syn --dport 80 -m connlimit --connlimit-above 50 -j REJECT --reject-with tcp-reset
this code is doing the work like firewall but I don't want to block of my server ips.
my server ips:
"127.0.0.1", "my server ip1", "my server ip2", etc.
How do I get them out of this ip tables rule?
Thank you very much!
Just use :
# Loopback
iptables -I INPUT -s 127.0.0.1 -i lo -j ACCEPT
# Repeat for each SERVER_IP
iptables -I INPUT -s SERVER_IP -j ACCEPT
Note that this will open everything for SERVER_IPs. YMMV depending on want you want to allow.
For instance, if you just want to open HTTP port for those IPs :
# Loopback
iptables -I INPUT -s 127.0.0.1 -i lo -j ACCEPT
# Repeat for each SERVER_IP
iptables -I INPUT -s SERVER_IP -p tcp --dport 80 -j ACCEPT
Related
I have been trying for some time to configure my Proxmox with a PFSense VM filtering internet traffic to my other VMs.
So far I have managed to install PFSense and configure the Proxmox interfaces. I have also managed to go to the PFSense web interface. However, my VMs do not always have access to the internet, so I try to modify my iptables to manage to redirect all the traffic on PFSense.
Here are my interfaces:
interfaces
On the shell I did this operation :
cat > /root/pfsense-route.sh << EOF
#!/bin/sh
## IP forwarding activation echo 1 > /proc/sys/net/ipv4/ip_forward
## Rediriger les paquets destinés au LAN pour l'interface WAN de la PFSense ip route change 192.168.9.0/24 via 10.0.0.2 dev vmbr1 EOF
And I modified the file /etc/hosts :
[...]
auto vmbr2
iface vmbr2 inet static
address 192.168.9.1/24
bridge-ports none
bridge-stp off
bridge-fd 0
post-up /root/pfsense-route.sh
#LAN
And now the heart of the problem, the iptables. Here is my current file :
#!/bin/sh
# ---------
# VARIABLES
# ---------
## Proxmox bridge holding Public IP
PrxPubVBR="vmbr0"
## Proxmox bridge on VmWanNET (PFSense WAN side)
PrxVmWanVBR="vmbr1"
## Proxmox bridge on PrivNET (PFSense LAN side)
PrxVmPrivVBR="vmbr2"
## Network/Mask of VmWanNET
VmWanNET="10.0.0.0/30"
## Network/Mmask of PrivNET
PrivNET="192.168.9.0/24"
## Network/Mmask of VpnNET
VpnNET="10.2.2.0/24"
## Public IP => Your own public IP address
PublicIP="91.121.134.145"
## Proxmox IP on the same network than PFSense WAN (VmWanNET)
ProxVmWanIP="10.0.0.1"
## Proxmox IP on the same network than VMs
ProxVmPrivIP="192.168.9.1"
## PFSense IP used by the firewall (inside VM)
PfsVmWanIP="10.0.0.2"
# ---------------------
# CLEAN ALL & DROP IPV6
# ---------------------
### Delete all existing rules.
iptables -F
iptables -t nat -F
iptables -t mangle -F
iptables -X
### This policy does not handle IPv6 traffic except to drop it.
ip6tables -P INPUT DROP
ip6tables -P OUTPUT DROP
ip6tables -P FORWARD DROP
# --------------
# DEFAULT POLICY
# --------------
### Block ALL !
iptables -P OUTPUT DROP
iptables -P INPUT DROP
iptables -P FORWARD DROP
# ------
# CHAINS
# ------
### Creating chains
iptables -N TCP
iptables -N UDP
# UDP = ACCEPT / SEND TO THIS CHAIN
iptables -A INPUT -p udp -m conntrack --ctstate NEW -j UDP
# TCP = ACCEPT / SEND TO THIS CHAIN
iptables -A INPUT -p tcp --syn -m conntrack --ctstate NEW -j TCP
# ------------
# GLOBAL RULES
# ------------
# Allow localhost
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
# Don't break the current/active connections
iptables -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
# Allow Ping - Comment this to return timeout to ping request
iptables -A INPUT -p icmp --icmp-type 8 -m conntrack --ctstate NEW -j ACCEPT
# --------------------
# RULES FOR PrxPubVBR
# --------------------
### INPUT RULES
# ---------------
# Allow SSH server
iptables -A TCP -i \$PrxPubVBR -d \$PublicIP -p tcp --dport 22 -j ACCEPT
# Allow Proxmox WebUI
iptables -A TCP -i \$PrxPubVBR -d \$PublicIP -p tcp --dport 8006 -j ACCEPT
### OUTPUT RULES
# ---------------
# Allow ping out
iptables -A OUTPUT -p icmp -j ACCEPT
### Proxmox Host as CLIENT
# Allow HTTP/HTTPS
iptables -A OUTPUT -o \$PrxPubVBR -s \$PublicIP -p tcp --dport 80 -j ACCEPT
iptables -A OUTPUT -o \$PrxPubVBR -s \$PublicIP -p tcp --dport 443 -j ACCEPT
# Allow DNS
iptables -A OUTPUT -o \$PrxPubVBR -s \$PublicIP -p udp --dport 53 -j ACCEPT
### Proxmox Host as SERVER
# Allow SSH
iptables -A OUTPUT -o \$PrxPubVBR -s \$PublicIP -p tcp --sport 22 -j ACCEPT
# Allow PROXMOX WebUI
iptables -A OUTPUT -o \$PrxPubVBR -s \$PublicIP -p tcp --sport 8006 -j ACCEPT
### FORWARD RULES
# ----------------
### Redirect (NAT) traffic from internet
# All tcp to PFSense WAN except 22, 8006
iptables -A PREROUTING -t nat -i \$PrxPubVBR -p tcp --match multiport ! --dports 22,8006 -j DNAT --to \$PfsVmWanIP
# All udp to PFSense WAN
iptables -A PREROUTING -t nat -i \$PrxPubVBR -p udp -j DNAT --to \$PfsVmWanIP
# Allow request forwarding to PFSense WAN interface
iptables -A FORWARD -i \$PrxPubVBR -d \$PfsVmWanIP -o \$PrxVmWanVBR -p tcp -j ACCEPT
iptables -A FORWARD -i \$PrxPubVBR -d \$PfsVmWanIP -o \$PrxVmWanVBR -p udp -j ACCEPT
# Allow request forwarding from LAN
iptables -A FORWARD -i \$PrxVmWanVBR -s \$VmWanNET -j ACCEPT
### MASQUERADE MANDATORY
# Allow WAN network (PFSense) to use vmbr0 public adress to go out
iptables -t nat -A POSTROUTING -s \$VmWanNET -o \$PrxPubVBR -j MASQUERADE
# --------------------
# RULES FOR PrxVmWanVBR
# --------------------
### Allow being a client for the VMs
iptables -A OUTPUT -o \$PrxVmWanVBR -s \$ProxVmWanIP -p tcp -j ACCEPT
For now with this I still manage to go on my VMs in proxmox, but I’m not internet access on it. Moreover, the shell of my server is no longer accessible on proxmox and SSH connections are no longer accessible.
Some details:
I use port 22 as ssh port
My server ip is 91.121.134.145
My version of linux is Debian 10 (Buster)
Honestly I don’t know where the problem comes from, I’m a beginner and I find the majority of this configuration on the internet. If you see what is wrong I would be very happy to have the answer! In the meantime I thank you in advance for your reading and your answers!
Edit :
I tried to pass the iptables in legacy mode using these commands :
update-alternatives --set iptables /usr/sbin/iptables-legacy
update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy
update-alternatives --set ebtables /usr/sbin/ebtables-legacy
Only this command to refuse to work :
update-alternatives --set arptables /usr/sbin/arptables-legacy
Moreover I don’t know why but my VMs have good access to the internet, the problem is therefore centered on the SSH port that no longer works (I can no longer go on the shell since proxmox)
I can set iptables rules to prevent external connection. But can we use iptables to prevent internal connection? For example, I have set iptables to prevent port 5555 port on my machine, but my local APP can still connect with 5555 when running on my machine.
Yes you can block it using iptables.
iptables -A INPUT -d 127.0.0.1 -p tcp --dport 5555 -j DROP
With this command you'll not be able to connect from your own host to your own service. Then you can remove the rule using the opposite to -A append which is -D delete:
iptables -D INPUT -d 127.0.0.1 -p tcp --dport 5555 -j DROP
Hope it helps.
Depends upon how you are blocking the port 5555, if you have a specific INPUT rule with interface and source and/or destination addresses it would match only those. In your case, you could modify your rule to just match tcp destination port 5555 and it will block all packets to tcp destination port 5555. for eg:
iptables -t filter -I INPUT -p tcp --dport 5555 -j DROP
If you just want to block your internal apps and not touch your existing iptables rule then use the incoming interface as lo for eg:
iptables -t filter -I INPUT -i lo -p tcp --dport 5555 -j DROP
Note: If you are using destination ip then use the entire loopback address range rather than just 127.0.0.1 for eg:
iptables -t filter -I INPUT -d 127.0.0.0/8 -p tcp --dport 5555 -j DROP
Before you do any changes you can instead of -j DROP action use -j LOG action to log and confirm the tcp connections this rule will match. You could also skip the action part without specifying the -j option and check how many packets would match your rule with iptables -t filter -L -n -v without causing any harm.
I'm running Redis on my webserver (Debian/Nginx/Gunicorn) for session storage and have reasons to believe my Redis server is being hacked. It's definitely possible because if I run the command "redis-cli -h (HOST IP)" on a different machine against the web server, I can get into the console and run commands. I have two questions. First, if I add a new section to my iptables files as shown below, will I be correctly blocking access to my Redis server from all machines except the webserver itself? Redis is running on the default port 6379.
*filter
-A INPUT -i lo -j ACCEPT
-A INPUT ! -i lo -s 127.0.0.0/8 -j REJECT
# Allow pings, SSH, and web access
-A INPUT -p icmp -m state --state NEW --icmp-type 8 -j ACCEPT
-A INPUT -p tcp --dport 22 -m state --state NEW -j ACCEPT
-A INPUT -p tcp --dport 80 -m state --state NEW -j ACCEPT
-A INPUT -p tcp --dport 443 -m state --state NEW -j ACCEPT
# NEW SECTION...
# IS THIS CORRECT?
-A INPUT -p tcp --dport 6379 -j DROP
-A INPUT -p tcp -s 127.0.0.1 --dport 6379 -m state --state NEW -j ACCEPT
# END NEW SECTION
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -j REJECT
-A FORWARD -j REJECT
COMMIT
Second, if the above is correct, can I still use 127.0.0.1 in the IPv6 version of my iptables or do I need to use "::1"?
Thanks.
You should be able to do this through the Redis configuration file:
# By default Redis listens for connections from all the network interfaces
# available on the server. It is possible to listen to just one or multiple
# interfaces using the "bind" configuration directive, followed by one or
# more IP addresses.
#
# Examples:
#
# bind 192.168.1.100 10.0.0.1
# bind 127.0.0.1
modify redis.conf file :
bind 127.0.0.1 ==>
redis instanse will accept connections only from localhost
bind 127.0.0.1 xxx.xx.xx.xxx ==>
if you want to accept connections from out server add ip of the server
#bind 127.0.0.1 ==> comment this line will make redis listens from any network interface
I have an apache webservice running on port 8080 but would like to be able to connect on port 80. However, my unix sysadmin does not allow apache to be started as root nor does she provide access to sudo.
However, she will execute commands on request.
I believe this can be achieved with iptables. Is there a way to map port 80 to 8080 and 443 to 8083 without this sysadmin having to edit any files.
i.e. just using echo with appender >>.
She can do this by running :
iptables -t nat -I PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8080
iptables -t nat -I PREROUTING -i eth0 -p tcp --dport 443 -j REDIRECT --to-port 8083
This will make redirection active immediately, but doesn't save it and thus it will not work anymore after a reboot.
It is possible to do this without editing any file at all by using iptables-save. But it depends which linux flavor you're running, and if you use ferm, ufw, or some other firewall management tools.
On RedHat/CentOS, she could just do :
iptables -t nat -I PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8080
iptables -t nat -I PREROUTING -i eth0 -p tcp --dport 443 -j REDIRECT --to-port 8083
iptables-save > /etc/sysconfig/iptables
On other OSes variants, YMMV !
I can't access Plesk Amdin because of DOS attack; can I block a hostname or IP address through SSH? If so, how would I be able to do this?
Thank you!
If you have iptables you can block it using simple rule:
iptables -I INPUT --source 1.2.3.4 -j DROP
This rule drops packets coming from IP 1.2.3.4.
Probably the easiest is to SSH to your box use vim to and add the following to the top of your .htaccess file in the root of your domain (/var/www/vhosts/yourdomain.com/httpdocs/.htaccess):
deny from 12.345.67.89
Obviously replace the IP address with the one you want to block. Repeat this for any sites you think are being attacked.
iptables -I INPUT -p tcp -s 1.2.3.4 -m statistic --probability 0.5 -j DROP
iptables -I INPUT n -p tcp -s 1.2.3.4 -m rpfilter --loose -j ACCEPT # n would be an numeric index into the INPUT CHAIN -- default is append to INPUT chain
iptables -I INPUT -p tcp -m hashlimit --hashlimit-mode srcip -s 1.2.3.4 --hashlimit-srcmask --hashlimit-above 9/second -j DROP
iptables -I INPUT -p tcp -s 1.2.3.4 -m limit --sport 80 --limit 100/second -j ACCEPT
There are countless others for your circumstances.
Sincerely,
ArrowInTree