[Read Me](README.md) > FAQ
# Frequently Asked Questions
## Problem #1
I'm getting following error:
> unable to set up TCP listener: Permission denied (os error 13)
### Solution
Try to run rws with admin privileges.
## Problem #2
I'm getting following error:
> unable to set up TCP listener: Address already in use (os error 48)
### Solution
Some application is already using port 80.
Find out PID and stop it.
> sudo fuser 80/tcp # works on linux
>
> sudo lsof -i :80 # works on macOS as well as on linux
## Problem #3
I started rws on http://127.0.0.1:80,
but unable to query it from local network.
### Solution
Server is running on loopback device. Find out ip address
of you network device and restart rws
using provided ip.
> ifconfig # find ip address
## Problem #4
I'm not able to set cookies.
### Solution
Cookies are not implemented for Rust Web Server.
The reason behind it is safety concerns as
rws is a http server. As a developer you may use
[localStorage](https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage) or [sessionStorage](https://developer.mozilla.org/en-US/docs/Web/API/Window/sessionStorage) to bypass absence
of the cookies.
## Problem #5
I see the following error in the console:
> unable to parse request: invalid utf-8 sequence of _n_ bytes from index _m_
### Solution
Server received not properly encoded request in UTF-8 charset. Request may be sent from various software on your network. You can ignore this message. Also request may be done through https but server is on http protocol.
## Problem #6
I see the following error in the console:
> unable to parse request: Unable to parse method, request uri and http version
### Solution
Server received not valid request, for example it may contain a typo or [ASCII invisible control characters](https://en.wikipedia.org/wiki/Control_character). Request may be sent from various software on your network. You can ignore this message.
## Problem #7
I see the following error in the console(**Linux**):
> unable to set up TCP listener: Cannot assign requested address (os error 99)
>
### Solution
Most probably you are trying to start server on port 80. To start server on port 80 try to run it as an administrator or user with admin privileges.
## Problem #8
How do I start server on IPv6?
### Solution
Simply start server with -ip=:: (or -i=::).
## Problem #9
I have started server on ip=:: but unable to access it via fe80::... address.
### Solution
Try to access the server using IPv4 _inet_ address, from the same interface. Internally your IPv4 address will be converted to IPv6 variant [::ffff:192.168.m.n].
## Problem #10
I'm trying to open directory, but getting _404 Not Found_ error.
### Solution
Directory listing is not implemented. The reason behind this decision is security. To eliminate accidental sharing of unintended files.
As a workaround you can create html file with list of files you need to make available.
## Problem 11
I'm not able to connect to server, getting error:
> Failed to connect to 192.168.m.n port x after y ms: Connection refused
### Solution
Most likely firewall is blocking incoming request, try to stop firewall and retry.
## Problem 12
I'm not able to start server as root
> Command not found
### Solution
Root does not have /usr/local/bin as part of his $PATH variable. Try to start server by explicitly specifying path to rws: _/usr/local/bin/rws_
UPDATE 26 Dec 2022: new guideline is to install to /usr/bin directory.
## Problem 12
I'm trying to build rws from source and getting the error:
> linker 'cc' not found
### Solution
You need to install development tools:
> sudo dnf group install "Development Tools" #RHEL and derivatives
>
> sudo yum install cmake make gcc #RHEL and derivatives
> sudo apt-get install build-essential # Ubuntu and derivatives
>
> sudo apt-get install make gcc cmake # Ubuntu and derivatives
> sudo pacman -S base-devel # Arch Linux
## Problem 13
While building from IDE getting error:
> error[E0514]: found crate `NAME` compiled by an incompatible version of rustc
### Solution
Usually whenever such error encountered by me, I'm performing clean and build from the console, eliminating the built-in IDE compilation, and it works fine.
> cargo clean
>
> cargo build
## Problem 14
While building from IDE getting error:
> error: failed to get `NAME` as a dependency of package `NAME VERSION
>
> failed to load source for dependency `rust-web-server`
>
> Unable to update registry `crates-io`
>
> failed to fetch `https://github.com/rust-lang/crates.io-index`
>
> failed open - 'PATH.git/FETCH_HEAD' is locked: Permission denied; class=Os (2); code=Locked (-14)
### Solution
Usually whenever such error encountered by me, I'm performing clean and build from the console as an administrator, eliminating the built-in IDE compilation, and it works fine.
> sudo cargo clean
>
> sudo cargo build
## Problem 15
While getting sources getting an error:
> The following untracked working tree files would be overwritten by merge (checkout): Cargo.lock
### Solution
Delete `Cargo.lock`, it will be regenerated automatically.
> rm Cargo.lock
## Problem 16
Why some methods start from `_` (like `pub fn _generate_request(request: Request) -> String ` in `Request`)?
### Solution
Compiler will throw a warning, to eliminate this warning some of the methods named starting with underscore `_`.
## Problem 17
I can see logs in the commandline, how can I see logs from server via http?
### Solution
Simply output console output to file `./rws &> out.txt` and open the file via `http://hostname:port/out.txt`. Logs will be appended to file, so the log file may become large and potentially even fill the filesystem.