Okay so I have been on Google for about an hour or so trying to figure this one out.
I have a L2TP/IPSec vpn setup. When clients connect a new interface is created for that client the issue is durning boot and most of the time these interfaces do not exist. My vpn range starts at 10.24.1.1 I want sshd to listen on 10.24.1.1 but when there is no client connected it failes to bind address
/var/log/secure:
Apr 15 01:38:26 arija sshd[28068]: error: Bind to port 22 on 10.24.1.1 failed: Cannot assign requested address.
which makes sense. My Question is. Is there a way to create some sort of dummy interface or just assign 10.24.1.1 so sshd will listen on it? Thanks for the help!!
Also Server is CentOs 6 64bit
you can just add the ip address you need to the interface during startup
the configuration depends on which linux flavor you're using, as an example for ubuntu it's located in /etc/network/interfaces.d/eth0.cfg.
Make sure you're excluding this address from the address pool you are using to provision IP Addresses to the L2tP clients
First of all, you need to understand, that in common situation service can listen only on 'up-and-running' interface with assigned IP. The reason of this is Linux core limitations. You can change this behavior at runtime with:
sysctl net.ipv4.ip_nonlocal_bind=1
or at boot time by setting same parameter in /etc/sysctl.conf:
...
net.ipv4.ip_nonlocal_bind=1
...
But there is simpler way for you: you can bind sshd to 0.0.0.0 in their config /etc/ssh/sshd_config:
...
ListenAddress 0.0.0.0
...
Related
I am trying to set up a STUN/TURN server on my local computer for a webrtc application of me. I decided to use coturn. Note that my server is running behind a NAT.
So i fired up my Ubuntu VM and installed it. After reading through the wiki I got it working, atleast on my local network. For testing purposes, i use this site. Therefore, when i try it there with 192.168.178.25:3478, it works. When i try it with "public-ip":3478, it doesnt.
This told me, it is working locally and it should be a port/NAT issue. What i did:
1) I set the VM to Bridging
2) I opened the port 3478 on my router. To test if this is really working, i used telnet on a remote machine and it worked. Another test was that i set up a quick apache server on my local machine on port 3478 and it could be accessed from the outside. This told me that there is, or should be, not port/NAT issue and my turn server should be working.
Any ideas?
I am running my server with the following command:
"sudo turnserver -X "public-ip" -listening-port=3478 -v
The turnserver.conf looks something like this:
fingerprint
realm="myRealm"
lt-cred-mech
user=test:test
As telnet and apache server are both working, i am pretty sure i have a configuration issue. I basically spent the weekend trying and im really lost on what could be wrong.
Thanks for any help!
From the documentation of turnserver
-X, --external-ip <public-ip>[/private-ip] TURN Server public/private address mapping, if the server is behind NAT. In that situation, if a -X is used in form "-X " then that ip will be reported as relay IP address of all allocations. This scenario works only in a simple case when one single relay address is to be used, and no CHANGE_REQUEST STUN functionality is required. That single relay address must be mapped by NAT to the 'external' IP. The "external-ip" value, if not empty, is returned in XOR-RELAYED-ADDRESS field. For that 'external' IP, NAT must forward ports directly (relayed port 12345 must be always mapped to the same 'external' port 12345). In more complex case when more than one IP address is involved, that option must be used several times, each entry must have form "-X ", to map all involved addresses. CHANGE_REQUEST NAT discovery STUN functionality will work correctly, if the addresses are mapped properly, even when the TURN server itself is behind A NAT. By default, this value is empty, and no address mapping is used.
So, it is not enough that you expose only the listening port from the inside LAN to the public network but all ports that you are going to use to relay. Please, note what is said in the same documentation:
--min-port <port> Lower bound of the UDP port range for relay endpoints allocation. Default value is 49152, according to RFC 5766.
--max-port <port> Upper bound of the UDP port range for relay endpoints allocation. Default value is 65535, according to RFC 5766.
You should choose a range of ports in the server, configure with them the options --min-port and --max-port and create a NAT rule to expose those ports to the public side of the router without change.
log:Creating Server TCP listening socket （myip:port）: bind: Cannot assign requested address
my redis.conf
bind 10.114.234.11
when i cofig like this
bind 127.0.0.1
it works well
You likely do not currently have any interfaces set up for the 10.x.x.x subnet. If you're on any flavor of Linux, ifconfig should be able to tell you which interfaces are currently set up. For example, I'm running Mint 17:
$ ifconfig | grep "inet addr"
inet addr:127.0.0.1 Mask:255.0.0.0
inet addr:192.168.1.3 Bcast:192.168.1.255 Mask:255.255.255.0
So I (like you) would not be able to bind Redis (or most any other service requesting a TCP socket) to 10.x.x.x. If you are really trying to listen for connections on that subnet, you will need to change your network setup (how exactly that would be done depends largely on your operating system).
I also faced same issue while setting up redis for remote access. I was using google cloud platform and we created Google compute engine VM instance where we installed our Redis server. Redis doesn't ship with by default with security configured. You have to perform some steps to secure it. By updating IP address in redis.conf in bind will allow access only from that IP addresses. When we were doing it, we were getting same error.
To solve this issue we haven't added IP addresses in redis.conf file instead in Google cloud firewall rules when we add port open record in network -> IP ranges you can specify IP address which you want allow to access redis. In redis.conf file update from bind 127.0.0.1 to bind 0.0.0.0. So basically we will restrict it from Google cloud firewall rules dashboard.
Below are steps to add IP address restrictions:
Login to your google cloud console
Navigate to VPC Network -> Firewall Rules
Click on CREATE FIREWALL RULE or edit existing one if it's already there
In Source IP ranges add your IP address to allow access only - See below screenshot
Once you create this rule add this source tags under your VM instances network type and you are done.
I have faced the same issue when I changed the default redis.conf to custom Redis conf and after changing the bind as below then it started working, Please be aware that the below conf will open the Redis connection from all sources.
bind 127.0.0.1 -::1 to bind 0.0.0.0 -::1
At /etc/redis/redis.conf
Please change
bind 127.0.0.1 ::1
to
bind 0.0.0.0
then restart
/etc/init.d/redis-server restart
It's work to me
I can't access to AWS EC2 instance from one day.
(AMI: ubuntu/images/ebs/ubuntu-precise-12.04-amd64-server-20121001 (ami-22ad1223))
$ ssh -v -i mykey.pem ubuntu#XXX.XXX.XXX.XXX
OpenSSH_5.9p1, OpenSSL 0.9.8x 10 May 2012
debug1: Reading configuration data /etc/ssh_config
debug1: /etc/ssh_config line 20: Applying options for *
debug1: Connecting to xxx.xxx.xxx.xxx [xxx.xxx.xxx.xxx] port 22.
debug1: connect to address xxx.xxx.xxx.xxx port 22: Operation timed out
ssh: connect to host xxx.xxx.xxx.xxx port 22: Operation timed out
This is my "Security Groups" setting in EC2.
I did not change the setting from the time had a good connection.
Ports Protocol Source
22 tcp 0.0.0.0/0
80 tcp 0.0.0.0/0
3000 tcp 0.0.0.0/0
3006 tcp 0.0.0.0/0
I've tried many times to restart the server.
Web server is going well. However SSH connection is not.
What could be problem and how to make it work?
My usual checklist:
On AWS console: is the Instance up and healthy?
Is it in a public Subnet?
Does it have a public ip?
Does the VPC have an associated Internet Gateway?
Does it have the Routing Table to the Internet Gateway? (Attached to the subnet?)
Are the Network ACL rules default?
Does the Security group allow ping? If yes, does the ping work?
Does the Security group allow SSH inbound?
If there is still no clue, then fire up a new instance (from a base AMI) in the same VPC. Connect to it via SSH. If it was successful, try to ssh from that instance.
I too faced the same issue. Actually, by mistake, I deleted the default Internet Gateway.
Go to VPC and click "Internet Gateways" from the left menu.
Click "Create internet gateway" button and provide Name tag (any name - optional) and click create.
By default, it is detached. So click the Actions drop-down and select "Attach to VPC" and attach it with default VPC
Now go to "Route Table" and select default route table and edit the route by clicking "Edit routes" button under Routes tab
Then in the Destination text box provide "0.0.0.0/0" and in target select the newly created Internet gateway (starts with igw-alphanumeric) and save the route.
Now you should be able to SSH EC2 instance.
For newbies to AWS, like me, remember the hostname can change if you reboot or stop/start your instances. So remember to use the right hostname - visible in the description of your instance each time you ssh.
If this happens "from one day", the IP your AWS EC2 instance associated with may be blocked from this day.
If the IP is blocked, you need to add a new dynamic IP and associate this new dynamic IP with your AWS EC2 instance.
Steps:
1.Go to "Elastic IPs".
2.Allocate new address.
3.Choose this new address. Click "Actions" and "Associate address".
4.Select your instance and Click "Associate".
In my case, adding new dynamic IP to my AWS EC2 instance fix the problem.(My problem was I can't access to AWS EC2 instance from one day too)
Kindly create a new security group and select type SSH
SSH
TCP
22
0.0.0.0/0
In addition to Adam's answer, also check if your public subnet's RT table is using the IGW and the private Subnets' RT has 0.0.0.0/0 -> NAT instance Id.
Check that you are connecting to the public dynamic IP or associate an ElasticIP and connect to it.
I was using public wifi in the library and that was not letting me connect, which I came to know when I switched to my mobile hotspot wifi (password protected). Try switching to a protected network.
Even I also faced this same problem, good to know i have not allowed from route table.
Check EC2 Instance associated
And try these steps
subnet,Route table and allowed CIDR blocks
key pair associated with EC2 Instance
security group ssh port 22 allowed or not.
If you are accessing from a new machine, then make sure the IP of the machine you are accessing from is included in the inbound rules. If not add a rule
SSH | TCP | Port:22 | Source: MY IP
For me, I had to delete all my rules for the security group for the particular instance and create new rules for the same ssh, http and https
For some reason after stopping the instance and starting it later, my IP changed... probably because I switched my wifi connectivity device.
But putting new rules with the new IP address worked! You can check the ip by googling "myip"
Well, if this happened all of a sudden, try disconnecting and connecting back to your VPN (if accessing through a VPN). It might work!
I was able to fixed it simply by following this instruction
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/get-set-up-for-amazon-ec2.html
It sets up your private key pair as well as security group. The issue I think mainly because the default security group doesn't has a ssh inbound for your local IP setup.
If none of the troubleshooting steps above work for you, make sure that your EC2 container meets all system requirements for the application(s) you're running on the container. SSH will sometimes not be able to start if the memory runs out before getting to the SSH service.
Example: I was perfectly able to SSH into my EC2 container when I first launched it. I then proceeded to install Mailcow. My issue with SSH arose after restarting my container because the application I had installed required heavy services -- Docker, for example. After reading the system requirements from Mailcow, I realized a t2.micro wasn't even close to what I needed to run everything. I changed to a t3.large, and all worked perfectly.
Even after doing this for awhile, you can sometimes forget the most basic steps and requirements.
Try stopping the ec2 instance and then restarting. It worked for me!
In the redis.conf the normal setting is
bind 127.0.0.1
I want redis to listen to another ip too (say my local development address)
I tried
bind 127.0.0.1, 123.33.xx.xx
but this does not work. I cannot find any relevant in the document or by googling. Hope someone can help.
Binding to multiple IPs is indeed possible since Redis 2.8. Just separate each IP by whitespace (not commas).
bind 127.0.0.1 123.33.xx.xx
Source: Official default config
This answer is not outdated and will work for both older and newer versions
The problem in understanding is that Redis binding doesn't show the client machine's address, but shows the interface through which connection should be established. In your example, if your local development (client) address is 123.33.xx.xx, it doesn't mean that you have to put exactly the same address as a binding, otherwise Redis service will not start.
So if ifconfig on your Redis server machine shows that you have some network interface similar to this:
eth0 Link encap:Ethernet HWaddr 00:0c:...
inet addr:192.168.1.110 Bcast:192.168.1.255 Mask:255.255.255.0
you can put the interface's address 192.168.1.110 as a binding and every request to Redis, which pass through this interface, should succeed.
Since:
--[ Redis 2.8 Release Candidate 1 (2.7.101) ] Release date: 18 Jul 2013
you can:
[NEW] Ability to bind multiple IP addresses.
Cheers!!
Edit: it seems that the correct way is, still, only one line and one or more IPs separated by space
This way:
bind 127.0.0.1 10.150.220.121
EDIT: This is an outdated answer. Please check newer answers for solution.
You cannot set redis to listen on specific multiple interfaces. If multiple interfaces are required just remove the bind line.
As #taro pointed out use firewall to restrict access.
I tried finding that answer too, as it stands, it's not possible to do this, I found this while searching for the answer on multiple (but not all interfaces). This is what turned up http://code.google.com/p/redis/issues/detail?id=497 stating it will not be supported by redis itself.
In conjunction with haproxy that makes it impossible to put it in front of redis in one go. You need to use a different port, or the other or choose to bind on 1 IP.
The only way this worked for me, was by adding separate lines:
bind 111.222.33.44
bind 127.0.0.1 ::1
bind 127.0.0.1 192.168.152.2
Note, I have to put the 127.0.0.1 first otherwise the 192.x will not be bound at system boot. However another systemctl restart redis will suffice -- might be a bug? (Debian 10 and Redis 5.0.3)
For macOS Homebrew installation, make sure you are editing /usr/local/etc/redis.conf instead of the template file: /usr/local/Cellar/redis/6.2.6/.bottle/etc/redis.conf
My question may be a little confusing, but anyway. My school is going to open up WiFi DMZ on separate IP for students, but they said port 80 will be the only port open.
What do I want? Well I want to tunnel my traffic thru my home server, which is running Apache2 on 80 and SSH on 21. It's just a regular setup. As it is a production machine and I want clients to be able to connect on port 80, but I want to connect to port 80 to make a tunnel. The question is: How to do that?
The possible sollution: Abandon possibility of connecting to websites running on the server from the school IP and use IPTABLES. If source ip == $school_ip && port == 80: Redirect to port 21. Done. But I think there must another, elegant sollution... Isn't it possible to actually use the HTTP transfer for SSH transit? I mean create a host named for example ssh.mydomain.tld and use some apache module to do a server-side redirection to port 21 but only on that particular hostname? What can I do?
Box is running Debian GNU/Linux
Thanks for any help...
Off topic: They think they will block any sort of illegal operation. In fact HTTP is probably the second most-vulnerable protocol after BitTorrent. Why don't lock it down too? It'll be absolutely safe if there's no open ports, wouldn't it? I don't personally think blocking ports for POP, IMAP, Jabber, etc is any good. I think they'll probably seriously piss someone off if they even can't open mail teacher sent them. Oh, there's a webmail? No no no! SSL/TLS goes on port 443, remember? I don't think blocking all the traffic will be any good. IMO they should block unencrypted BitTorrent and apply low-priority QoS for unclassified transfers.
You could try the instructions found here:
http://dag.wieers.com/howto/ssh-http-tunneling/
proxytunnel is available in the stable repo:
http://packages.debian.org/search?keywords=proxytunnel&searchon=names&suite=stable§ion=all
A simple and working solution is sslh.
It is exactly the tool to solve that problem.
BTW ssh is usually set on port 22.