Possible reasons for timeout when trying to access EC2 instance

Question

I cannot SSH into my instance - Operation timed out  What could be the reasons why  and what can  I do to resolve it  Rebooting normally takes a long time to take effect  and might just makes things worst  UPDATE  It is not about permissions - i can log in normally just fine  I suspect it might be because of memory issues

User · Answer

Destroy and create anew

I had one availability zone where I could connect and another where I could not. After a few hours I got so frustrated that I deleted everything in that availability zone.

Building everything back I had to make sure to create EVERYTHING. This included:

Create VPC
- CIDR: 10.0.0.0/24
Create Internet Gateway
Attach Internet Gateway to VPC
Create Routing Table
Add Route to Routing Table
- Destination: 0.0.0.0/0
- Target: <Internet Gateway from earlier>
Create Subnet
- CIDR: 10.0.0.0/24
- Routing Table: <Routing Table from earlier

It took me a LOT of fumbling to get all of this. I've ordered the steps in the way I think might be most efficient, but you may have to adjust them to get one item available for the next.

Suggestion

I'm not suggesting that you go thermo nuclear as I did. I'm offering all this information so that you can check these associations to ensure yours are appropriate.

User · Answer

I had the same problem  and the solution ended up being adding my local machine s IP to the list of inbound rules in the active security  group  In the inbound dialog below  enter 22 in the port range  your local IP 32 in the source field  and leave  custom tcp rule  in the dropdown

User · Answer

Allow ssh and port 22 from ufw  then enable it and check with status command  sudo ufw allow ssh sudo ufw allow 22 sudo ufw enable sudo ufw status

User · Answer

My issue - I had port 22 open for  My IP  and changed the internet connection and IP address change caused  So had to change it back

User · Answer

I was working on the instance and it was fine  the very next day when I tried to SSH into my instance it said - Connection timeout    I tried to go through this post but nothing worked  So I did -  On the Edit inbound rules from source column choose MY IP and it will automatically populate your Public IP address in CIDR format  XXX XXX XXX XX 32    I tried with the  ted strauss answer by giving local IP but it did not help in my case  So I choose MY IP and it worked    Hope this helps someone

User · Answer

This answer is for the silly folks  like me   Your EC2 s public DNS might  will  change when it s restarted  If you don t realize this and attempt to SSH into your old public DNS  the connection will stall and time out  This may lead you to assume something is wrong with your EC2 or security group or    Nope  just SSH into the new DNS  And update your    ssh config file if you have to

User · Answer

Just reboot the Ec2 Instance once you applied Rules

User · Answer

Check out this help page on AWS docs    http   docs aws amazon com AWSEC2 latest UserGuide TroubleshootingInstancesConnecting html TroubleshootingInstancesConnectionTimeout You will probably find your solution there  for me this part did the fix        EC2-VPC  Check the route table for the subnet  You need a route that   sends all traffic destined outside the VPC to the Internet gateway for   the VPC          Open the Amazon VPC console at https   console aws amazon com vpc     In the navigation pane  choose Internet Gateways  Verify that there is an Internet gateway attached to your VPC  Otherwise  choose Create   Internet Gateway and follow the directions to create an Internet   gateway  select the Internet gateway  and then choose Attach to VPC   and follow the directions to attach it to your VPC    In the navigation pane  choose Subnets  and then select your subnet    On the Route Table tab  verify that there is a route with 0 0 0 0 0 as the destination and the Internet gateway for your VPC as the   target  Otherwise  choose the ID of the route table  rtb-xxxxxxxx  to   navigate to the Routes tab for the route table  choose Edit  Add   another route  enter 0 0 0 0 0 in Destination  select your Internet   gateway from Target  and then choose Save       But I suggest you check out all the options the link above covers   you may find there the one or more issues that you got

User · Answer

For me it was the apache server hosted on a t2 micro linux EC2 instance  not the EC2 instance itself    I fixed it by doing    sudo su  service httpd restart

User · Answer

I had the same problem  and the solution was allowing access from anywhere to the list of inbound rules in the active security group  In the inbound dialog  enter 22 in the port range  anywhere in the source field  and select  ssh  in the dropdown   P S   This might not be the recommended solution as it means this instance can be ssh ed from any machine  but I could not get it to work with my local IP

User · Answer

I had the same problem and I solved it by adding a rule to the security Groups  Inbound SSH 0 0 0 0 0  Or you can add your IP address only

User · Answer

Building off  ted strauss s answer  you can select SSH and MyIP from the drop down menu instead of navigating to a third party site

User · Answer

One more possibility   AWS security groups are setup to work only with specific incoming ip addresses   If your security group is setup in this way you  or the account holder  will need to add your ip address to the security group   Todo this open your AWS dashboard  select security groups  select a security group and click on the inbound tab   Then add your ip as appropriate

User · Answer

If SSH access doesn t work for your EC2 instance  you need to check    Security Group for your instance is allowing Inbound SSH access  check  view rules     If you re using VPC instance  you ve VPC ID and Subnet ID attached to your instance   check    In VPC Dashboard  find used Subnet ID which is attached to your VPC  Check its attached Route table which should have 0 0 0 0 0 as Destination and your Internet Gateway as Target    On Linux  you may also check route info in System Log in Networking of the instance  e g                                          Net device info                                         -------- ------ ------------------------------ --------------- ------- -------------------    Device    Up              Address                   Mask       Scope       Hw-Address       -------- ------ ------------------------------ --------------- ------- -------------------      lo     True            127 0 0 1               255 0 0 0                                    eth0    True           172 30 2 226           255 255 255 0           0a 70 f3 2f 82 23    -------- ------ ------------------------------ --------------- ------- -------------------                              Route IPv4 info                               ------- ------------- ------------ --------------- ----------- -------    Route   Destination    Gateway        Genmask      Interface   Flags    ------- ------------- ------------ --------------- ----------- -------      0       0 0 0 0     172 30 2 1      0 0 0 0         eth0       UG        1       10 0 3 0     0 0 0 0     255 255 255 0     lxcbr0      U         2      172 30 2 0    0 0 0 0     255 255 255 0      eth0       U      ------- ------------- ------------ --------------- ----------- -------    where UG flags showing you your internet gateway   For more details  check  Troubleshooting Connecting to Your Instance at Amazon docs

User · Answer

To enable ssh access from the Internet for instances in a VPC subnet do the following    Attach an Internet gateway to your VPC  Ensure that your subnet s route table points to the Internet gateway  Ensure that instances in your subnet have a globally unique IP address  public IPv4 address  Elastic IP address  or IPv6 address   Ensure that your network access control  at VPC Level  and security group rules  at ec2 level  allow the relevant traffic to flow to and from your instance  Ensure your network Public IP address is enabled for both  By default  Network AcL allow all inbound and outbound traffic except explicitly configured otherwise

User · Answer

AFTER 2 HOURS I FOUND THIS  Note That ssh ip 120 138 105 251 32      IS NOT aws instance IP ADDRESS It Is not your local ip 127 0 0 1 It Is not your local ip localhost   BUT BUT BUT  Its Your public ip address of your personal Computer from which you trying to  access aws instance   Go to https   www whatismyip com   whatever ip address put in ssh   IF YOU WANT TO FULLY OPEN SSH TO ALL IP ADDRESS   THIS IS HOW FULLY ACCESSIBLE ENTRIES LOOK -  BASIC RECOMEENDED   THIS IS WHAT I AM USING IN PRODUCTION

User · Answer

If you ve just created a new instance and can t connect to it  I was able to solve the issue by terminating that one and creating a new one   Of course this will only work if it s a new instance and you haven t done any more work on it

User · Answer

Did you set an appropriate security group for the instance  I e  one that allows access from your network to port 22 on the instance   By default all traffic is disallowed    Update  Ok  not a security group issue  But does the problem persist if you launch up another instance from the same AMI and try to access that  Maybe this particular EC2 instance just randomly failed somehow      it is only matter of time that something like that happens   Recommended reading  Architecting for the Cloud  Best Practices  PDF   a paper by Jinesh Varia who is a web services evangelist at Amazon  See especially the section titled  Design for failure and nothing will fail

User · Answer

I had similar problem  when I was using public Wifi  which didn t have password  Switching the internet connection to a secure connection did solve the problem

User · Answer

The following are possible issues    The most likely one is that the Security Group is not configured properly to provide SSH access on port 22 to your i p  Change in security setting does not require a restart of server for it to be effective but need to wait a few minutes for it to be applicable  The local firewall configuration does not allow SSH access to the server    you can try a different internet connection  your phone dongle to try it  The server is not started properly   then the access checks will fail even on the amazon console   in which case you would need to stop and start the server

User · Answer

ping the DNS first   If fails then configure your inbound outbound rules in the launch wizard   configure ALL traffic and ALL protocol and just save with default options   Ping again with your local system and then should work

User · Answer

To connect use ssh like so   ssh -i keyname pem username xxx xx xxx xx   Where keyname pem is the name of your private key  username is the correct username for your os distribution  and xxx xx xxx xx is the public ip address    When it times out or fails  check the following   Security Group  Make sure to have an inbound rule for tcp port 22 and either all ips or your ip  You can find the security group through the ec2 menu  in the instance options   Routing Table  For a new subnet in a vpc  you need to change to a routing table that points 0 0 0 0 0 to internet gateway target  When you create the subnet in your vpc  by default it assigns the default routing table  which probably does not accept incoming traffic from the internet  You can edit the routing table options in the vpc menu and then subnets   Elastic IP  For an instance in a vpc  you need to assign a public elastic ip address  and associate it with the instance  The private ip address can t be accessed from the outside  You can get an elastic ip in the ec2 menu  not instance menu     Username  Make sure you re using the correct username  It should be one of ec2-user or root or ubuntu  Try them all if necessary    Private Key  Make sure you re using the correct private key  the one you download or choose when launching the instance   Seems obvious  but copy paste got me twice

User · Answer

For me  it was that I had deleted everything from the boot volume  And couldn t connect to the instance anymore

User · Answer

Have you looked at the console output from the instance   You can do this via the AWS console  Instances -  Right-click on the instance -  Get System Log    I ve had occasions where the network services on an EC2 instance failed to start correctly  resulting in timed out SSH connections  restarting the instance usually fixed things

[ssh] Possible reasons for timeout when trying to access EC2 instance

Destroy and create anew

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