I have an ubuntu 14.04 server working as an internet gateway/router. When I run a continuous ping against a known good address on the internet, I get steady reply with good latency. But sometimes when I then try to start browsing web pages from my PC, the ping will timeout for a few seconds then start back up, like it had a hiccup or something. I can see the continuous ping timeout, report destination host unreachable and report high latency up as much as 14k ms before it returns to normal. Its like whenever I try to browse a web page (been testing using amazon.com), its overloading the network and the router is failing while it catches up. I can duplicate this behavior about 90% of the time.

My ubuntu router is virtualized, otherwise everything is connected via wired gigabit connections. I've tried the ping from both a windows 8.1 pc and a ubuntu 14.04 server with the same results. I have a feeling I've got something misconfigured in the routing table but I haven't set up any special static routes or anything. Only thing the gateway is doing is NAT and port forwarding for 80, 443 and 25. I haven't tried any other type of traffic, don't really know what else I could test with. Has anyone else encountered a problem like this or can suggest other things I can check?

  • 1
    Let's point fingers at your internet connection first. If your setup basically works until you put load on it, it's probably not a configuration issue (or possibly it is a MTU issue - can you try pinging with larger packets?) – Brandon Xavier Sep 7 '15 at 22:45
  • its not my internet connection. I repoint my PC through a different linksys router going out through the same isp gateway just on a different public ip and it works just fine. It only occurs for traffic through the ubuntu gateway server. I haven't tried larger packets but I don't know networking that well, using this a teaching mechanism. What size should I try and what will that tell me? What am I looking for? What is MTU and what issue could it possibly be? – Raj Sep 8 '15 at 4:15

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