Received your file (attached) and went through it. Your proxy config seems to be the issue. If you say it works fine then after a while it stops it seems to be a case of resource exhaustion. For those familiar with squid your cache will die on you silently if you run out of HDD space - I think there's a similar case here. Either its memory running out or available connections. What are the specs of the PC running the proxy? Be sure to check the free RAM & HDD space under /system resource print Try these options: - Set max-cache-size to a definite value instead of leaving it unlimited - use the system resource output as a guideline. - Have you also tried checking its performance when you disable the proxy access rules? - You can also play with max-client-connections and raise it a bit - maybe there are many TIME_WAIT connections piling up that exhaust it (though I'm not 100% sure if they count towards this total). As for your proxy access rules...umenyonga watu kabisa. :) Have you read this? http://wiki.mikrotik.com/wiki/How_to_make_transparent_web_proxy Finally, perusing the mikrotik forums always helps as you almost always find someone asking a similar question: http://forum.mikrotik.com