Few days ago, I personally encountered a problem of browsing my personal blog URL https://tballah.blogspot.com, the website was intermittently working (to get connected). I contacted my ISP support for help to resolve this issue. With onsite presence, an ISP technician found out, after several troubleshooting, that using Google public DNS servers can get rid of such a problem; I am still not convinced about this fix suggested by the technician. After working for some time, the problem returns back; I need to find out the reason why this phenomenon happens. You can refer to my packet capture for the DNS resolution and TCP 3-way handshake prior to send HTTP request; you can observe that DNS query can successfully be resolved, and also there are many SYN packets sent to the host tballah.blogspot.com, there is no any SYN-ACK returned back from the host. According to the traceroute result, the SYN packets could not be passed through to reach the final destination.
My workaround solution is to configure the blue line below in /etc/hosts file (Windows also has such a host file located under %SystemRoot%\System32\drivers\etc\hosts)
172.217.26.129 blogspot.l.googleusercontent.com
Also the hop 118.69.255.57 needs to investigate the root cause for the routing of IP 74.125.24.132, while IP address 74.125.24.191 for blogger.com can pass through this hop. The workaround is just computer-based fix not recommended i.e. other users of my ISP will have the same problem I faced.
However, and undoubtedly, there are some benefits of using Google DNS service which is free to use and can be used by anyone who has access to the Internet. You can use Google DNS IP addresses instead of your ISP’s DNS servers to improve the resolve time and provide security. You can set them either on the router DHCP sever configuration or statically configure them on your network interface card (NIC).
Recently I figure out the issue which is from the DNS query response from tested DNS server such as 1.1.1.1, 8.8.8.8, and 202.58.98.202. If the query responds with the IP 74.125.24.132 for tballah.blogspot.com whose canonical name (CNAME) is blogspot.l.googleusercontent.com, the TCP packet (SYN) cannot go through the hop 118.69.255.57. If the query result responds with the IP 172.217.26.129 or 172.217.31.225, https://tballah.blospot.com is working. Please check the screenshot of each DNS query for every DNS server below:
My workaround solution is to configure the blue line below in /etc/hosts file (Windows also has such a host file located under %SystemRoot%\System32\drivers\etc\hosts)
172.217.26.129 blogspot.l.googleusercontent.com
Also the hop 118.69.255.57 needs to investigate the root cause for the routing of IP 74.125.24.132, while IP address 74.125.24.191 for blogger.com can pass through this hop. The workaround is just computer-based fix not recommended i.e. other users of my ISP will have the same problem I faced.
Theses are the Google public primary, and secondary DNS servers:
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