Networks such as the Bitcoin network were designed to be decentralized. However mining has centralized at a few major pools. This means rather than many nodes that cannot be DDoSed there are very few nodes that operate on these mining pools that could be attacked. The risk of this could stall the blockchain for an extended period of time, as if loads of hashrate suddenly dropped off the network if multiple pools were DDoSed this would stall the blockchain as the difficulty mechanism needs 2016 blocks to catch up and retarget.
You should always as a final failover when mining any coin have solo mining on you own node (or if this is unavailable, solo nodes that are publicly operated such as solo.ckpool.org). This way, if all major pools are DDoSed at once, the same amount of hashrate which was knocked offline will suddenly divert to solo nodes, ensuring transactions still get propagated and recorded in blocks, and has the side effect of awarding a lucky miner with a full block as if large numbers of miners failed over to solo mining they have the same chance of finding a block as in the pool and one of them is bound to as they would have been in a pool.
As you can see in the below chart, very few pools make up the network and it would only take DDoSing half of these to double or more the network average block solve time to slow it down or DDoSing all of them could stall the network completely:
This is a fatal flaw and the solution is simple, but yet rarely implemented.
If you have the resources to host your own node, this is highly recommended, it would add much redundancy to the network of Bitcoin, Litecoin or any cryptocurrency in general. As if enough miners did the above, no amount of DDoSing pools would stall the network. It is a vital layer of protection that is often missed our or underestimated. Using the stratum proxy you can set up your own node as a failover.
This would protect the Bitcoin and other blockchain networks greatly as a stall in the chain even for a few hours can be a disaster waiting to happen. So why wait? set up your own node, (best) or use a public solo node (next best option) and set that as your final miner failover today. You would be doing the network a great service.