Basil A's questions

After deleting a server {..} block from NGINX configuration and keeping two other server {..} block strange SSL errors starting showing up on the browsers:

• Chrome reported the error ERR_SSL_PROTOCOL_ERROR

• Firefox reported SSL_ERROR_RX_UNEXPECTED_NEW_SESSION_TICKET

• Curl reported gnutls_handshake() failed: An unexpected TLS packet was received

For some strange reason, these browser errors took place after removing one of the server {..} blocks and restarting NGINX. Running nginx -t before the restart showed a valid NGINX configuration with no problems. However, the restart introduced these problems.

I'm using Let's Encrypt certificates.

nginx -V

OUTPUT:
nginx version: nginx/1.14.0
built with OpenSSL 1.0.2g  1 Mar 2016
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -fPIE -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-Bsymbolic-functions -fPIE -pie -Wl,-z,relro -Wl,-z,now' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug --with-pcre-jit --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_v2_module --with-http_dav_module --with-http_slice_module --with-threads --with-http_addition_module --with-http_dav_module --with-http_flv_module --with-http_geoip_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_image_filter_module --with-http_mp4_module --with-http_perl_module --with-http_random_index_module --with-http_secure_link_module --with-http_v2_module --with-http_sub_module --with-http_xslt_module --with-mail --with-mail_ssl_module --with-stream --with-stream_ssl_module --with-threads --add-module=/build/nginx-1.14.0/debian/modules/headers-more-nginx-module --add-module=/build/nginx-1.14.0/debian/modules/nginx-auth-pam --add-module=/build/nginx-1.14.0/debian/modules/nginx-cache-purge --add-module=/build/nginx-1.14.0/debian/modules/nginx-dav-ext-module --add-module=/build/nginx-1.14.0/debian/modules/nginx-development-kit --add-module=/build/nginx-1.14.0/debian/modules/nginx-echo --add-module=/build/nginx-1.14.0/debian/modules/ngx-fancyindex --add-module=/build/nginx-1.14.0/debian/modules/nchan --add-module=/build/nginx-1.14.0/debian/modules/nginx-lua --add-module=/build/nginx-1.14.0/debian/modules/nginx-upload-progress --add-module=/build/nginx-1.14.0/debian/modules/nginx-upstream-fair --add-module=/build/nginx-1.14.0/debian/modules/ngx_http_substitutions_filter_module --add-module=/build/nginx-1.14.0/debian/modules/passenger/src/nginx_module

What configurations do I need to enable on sshd_config on a jump node server to be able to utilize that server using ProxyJump.

I have the following in my nginx configuration:

        # /abx/xyz/ 
        location /abc/xyz/ {
                allow 5.194.207.217;
                deny all;

                proxy_pass http://proxy-server/;
        }

        location /abc/ {
                proxy_pass http://proxy-server/;
        }

Whenever I access /abc/xyz it returns a 404 Not Found error. How can I make /abx/xyz work correctly?

I need a bash line to check if a ubuntu package needs an upgrade or not.

For example, I want to check if the package 'firefox' needs an upgrade using dpkg or apt-get commands.

Hypthetical Example:

# Hypothetical example pseudo-code
if [[ $(firefox_needs_upgrade) ]]; then echo "Firefox needs upgrading";fi

I can’t figure out why does an SSH public key file generated by ssh-keygen have a user and host at the end of it.

Example: id_rsa.pub

ssh-rsa ... rest of file ... /CA9gyE8HRhNMG6ZDwyhPBbDfX root@mydomain

Notice the root@mydomain at the end of the file.

If I can use the public key anywhere with any user to authenticate using my private key, what significance does the root@mydomain have on the authentication process?

Or is it just a place holder to figure our who was it issued by?

I'm looking for a tool to lookup a domain name through a DNS server and outputs the time it took to resolve. My requirement is that it should bypass the DNS cache.

Has anyone used such a tool?

NOTE: "dig" doesn't have any option to bypass the cache and therefore will not be useful in this case.

THE PROBLEM

I have multiple internet connections on a linux machine, I want each internet connection to use a specific DNS nameserver. /etc/resolv.conf is a problem, since it uses a global name server for all open internet connections.

Please note that the connections are all open and being used at the same time.

WHAT I NEED?

A way to say to linux the following:

Use DNS Nameserver A for internet connection 1

Use DNS Nameserver B for internet connection 2

Use DNS Nameserver C for internet connection 3

The problem is that /etc/resolv.conf uses the same nameserver for all conenections.

The exact requirement above I have to stick to.

Since the application I'm working on measure's ISP performance and DNS response time.

Using OpenDNS wont do me any good.

As for DHCP, I'm already obtaining DNS automatically from the ISP, but only the last DNS servers are being used in resolve.conf overwriting the previous name servers.

Need help.