Some network troubleshooting basics…
A fast, low latency experience is based on a fully working IP based networking, and on top of that a name resolution system… The two systems can be considered completely separate, each with its own possible issues and so need to be investigated separately.
Since name resolution is built on top of IP based networking, you need to establish no issues with your IP networking first. Your initial post and subsequent posts aren’t entirely clear that you’ve done your work completely on this first. Your traceroute post by IP address is important, and IMO your result while not exceedingly fast is within an acceptable window (no more than about 10-15ms latency). That result also shows that congestion didn’t happen until deeper towards the Internet which is beyond your ability to control and is your ISP’s problem. You need to run similar tests at least 3 times at various times of the day to see if your results vary, and to the Internet sites you connect to… Depending on where in the world you are and what you’re connecting to, your connection may be passing through congested networks at various times of the day. Save your results so you can build a profile what is happening and possibly present to your ISP as evidence they need to make changes… Your ISP has control not only of their own routers but also what gateways they use to connect to the Internet backbone providers and then on to your destinations. And, of course if you present evidence your ISP’s upstream provider itself is causing problems, then your evidence can be passed on to people who can address the problem.
When you have done all you can to address your IP based networking, only then can you then turn your attention to any name resolution issues, and for that you need to have an understanding of how the DNS system works. You can find many fully detailed descriptions around, but I’ll try to provide a brief description of the essentials you need to look at issues.
The first thing to know is that you can perform the identical PING and traceroute tests using names instead of IP addresses, remembering that if you don’t already know the effect of any IP based latencies, you can’t possibly identify any name resolution issues accurately.
You should also know that the DNS system is built on the idea that only one or a very few DNS have the most authoritative (ie original) records for your queries, but in the old days when machines were less powerful, if the world queried these few servers, they would be overwhelmed. So, it’s today possible for anyone (including your ISP) to set up their own DNS server to service their networks or customers but even then no single DNS server can be expected to hold all of the Internet’s addresses. The DNS system allows anyone to connect to any DNS server of their own choice to query for any address, and if the local DNS server doesn’t have that address, then the query is passed upstream to another server, and if that server doesn’t have the answer will pass it upstream again, repeating until the answer is found, and then the answer has to be passed back down the chain until it gets back to you. Unresolved queries don’t get passed upstream instantaneously, there is always a long delay of many, many seconds at each hop, so if the DNS server you’re using is very “remote,” the answer won’t be found and passed back downstream before you have timed out.
If you understand what has been described above, then it becomes clear that your choice of DNS can be important, you want to use either a very busy DNS server(which would probably be surprising to the student) or an “original” server that holds the records you need… And ISP DNS servers can be lacking in both. It used to be forbidden, but with today’s ample bandwidth and powerful hardware,it’s now acceptable to use DNS servers run by Internet giants like Google, IBM, major Internet ISPs, security companies, etc. And, they often have business interests for doing so, everyone that uses their DNS servers provides some information about how the Internet is behaving even if no private information is retained (well, you’d hope so but that’s company and service policy). This is why a troubleshooting solution for many is to use a Google name server (eg 220.127.116.11) instead of your ISP’s DNS.
When troubleshooting name resolution, you should use the “nslookup” utility. Get to know it, it’s extremely useful in a variety of situations, with it you can test and query not only your default name server, you can also temporarily connect to, test connections and query any other name server on the Internet… all without making any changes to your system like editing /etc/resolv.conf or making changes in YaST or Network Manager.
Troubleshoot step by step, the order in which you test can be important to isolate and build on top of information already gathered.
The tools you use (eg ping, traceroute, nslookup) and how they’re used are essential to gathering information.
Have confidence you’ll find your answer. If you’ve done a good job collecting relevant information but still aren’t able to analyze what you’re looking at, you can post and others will offer their own analysis.