51% Attack - Countermeasure Roundup: http://dot-bit.org/forum/viewtopic.php?f=2&t=308&p=2003#p2003

Are you already back on original blockchain? please confirm?!

Quick post. Unfortunately I have not much time. Running on way too small android mobile ATM.

BIG misunderstanding.

Please use your restore your namecoind from before starting on our "no longer ultra secret emergency branch" and use the current vinceds version! Please don't freak out. I'll help as soon as I'm at home. I prepared dispositions for paying miners after coordinated split who was mining on the original chain. We can use this funds to pay your miners on the new blockchain but you shouldquickly revert to a backup before block 19850 and catch up with the original blockchain. Please bear with me. I'll explain later as soon as i'm'm at home.

Dear MasterPool user


you are getting this email because you registered on MasterPool. I'd like to inform you about a severe issue on namecoin blockchain.

Due to the upcoming 51% attack to the namecoin network as outlined on the forums [1][2] MasterPool can not guarantee the safety of your namecoins. In fact if BitcoinEXpress will succeed with his attack and resets the blockchain to block 10000 all blocks ever mined on MasterPool will be undone. This is not only a problem with MasterPool but with all exchanges and pools. The attack is scheduled for block 19100.

At the moment the community is trying to mount countermeasures but it is still unclear if we get enough hashing power to counter this attack. So if you are unsure about what to do and want to be on the safe side it might be the best to withdraw all your namecoins from MasterPool, stop your namecoind, backup your wallet.dat AND your blockchain and wait for the storm to pass.

Your other option is to not withdraw your namecoins from MasterPool. However I CAN NOT guarantee for their safety. Thus you take the risk of loosing ALL your namecoins. I will however do my best to keep them safe. But if the blockchain is reset to block 10k they are gone anyway :-(

MasterPool will stay up during the time of attack. And we'll try to start merged mining on block 19200. If you are brave enough and want to help overcome this issue please consider to put all your available hashing power onto the namecoin blockchain. At the moment this seems to be the only possibility to effectively counter the attack. If you want to help secure the namecoin blockchain please register on at least one other pool to make sure you have an alternative if MasterPool is forced offline during this attack for any reason. Other namecoin pools are for example:

* DoubleC's Namecoin pool: http://bitparking.com/pool
* Davincij15's pool      : http://www.nmcbit.com/

Due to the attack Davincij15 offers a very competitive payment of 0.00003030 BTC (yes correct: bitcoins!) per namecoin share [3]. Thus if you are mining BTC in pay per share mode you might want to consider this offer in order to strengthen the namecoin network and get a bunch of bitcoins. Please tell your friends as well!


Happy mining!



[1] http://dot-bit.org/forum/viewtopic.php?f=2&t=292
[2] https://bitcointalk.org/index.php?topic=43465.0;all
[3] https://bitcointalk.org/index.php?topic=33612.msg521575#msg521575

Due to the possibly upcoming attack of BitcoinEXpress ( http://bit.ly/poTuzs ) MasterPool will start validating NMC blocks beginning with the next round until further notice. The current block will still be paid out directly.

Also see: https://www.masterpool.eu/jumble/comment/21

MasterPool started as a Namecoin Pool but was the first pool who implemented merged-mining (http://dot-bit.org/Merged_Mining).

The pool at a glance:

• first merged mining pool (and the only one who also was tested publicly on testnet so far)
• PPLNS payouts of block rewards including its transaction fees
• no mining fee substracted instead you pay a payout fee
• scheduled payouts each night (with 1% fee)
• instant payouts (with 2% fee)
• redundant master servers located in east and south germany
• email notifications
• micro forum for feedback, suggestions and small talk
• JSON stats for website and your miners

If you want to have a look at the pool I'd suggest to start on our statistics page: https://www.masterpool.eu/statistics. There you'll find a countdown for merged mining, too. If you want to start mining right away please join at: https://www.masterpool.eu/signup.

Das ist eine Vorhersage, die unheimlich schwer zu treffen ist. Selbst wenn man sagt, ich sage 10 Blöcke vorher per E-Mail Bescheid, so kann es durchaus sein, dass diese Blöcke innerhalb von kurzer Zeit gelöst werden, weil plötzlich viele Leute auf die Idee kommen Namecoins merged mining betreiben zu wollen. In der Vergangenheit war es so, wenn die Difficulty von NMC gesunken ist. Einige Blöcke vor dem Difficultychange zog die globale Hashrate dermaßen an, dass die letzten Blöcke innerhalb kurzer Zeit genommen wurden.

Aber ich könnte den Blockcount in die JSON API einbauen (https://www.masterpool.eu/faq/). So kann jeder eine eigene Implementierung bauen, und automatisiert prüfen, wieviele Blöcke bis zum Start noch fehlen. Besteht daran Interesse?

For namecoin it is already implemented and we are counting down to the block where merged mining will start: https://masterpool.eu/statistics

It's really a major update for the users of the blockchain which is mined additionally (called AUX chains) because you need all users to update to a new client. Using an old client will reject new clients blocks an vice versa as soon as merged mining start. At the moment I doubt it's possible with pump and dump blockchains. It took us several month on namecoin forum to agree on a block for merged mining. Furthermore for a merged mining pool you need a blockhain with some stable global hashrate .You can have surges in hashrate to some extend but you can't have a blockchain finding a block every few seconds. It's impossible to send long pollings for all blockchains every second like it was the case for some of those PnDcoins (Pump and Dump Coins). The merged mining pool would effectively be paralized and won't mine anything 

Einige erinnern sich vielleicht noch an den Merged Mining Thread. Ich wollte bekannt geben, dass Merged Mining in weniger als 385 Namecoin Blöcken startet. Der MasterPool hat dafür auch schon einen Countdown: https://www.masterpool.eu/statistics

MasterPool ist der bisher einzige Pool, der Merged Mining anbietet. Beim Merged Mining verbindet Ihr Euch zu dem Pool wie zu jedem normalen Bitcoinpool auch. Doch der Pool vergleicht jedes Ergebnis von eurem Miner nicht nur, ob es eine Lösung für die Bitcoin Blockchain ist, sondern auch, ob es eine Lösung für die Namecoin Blockchain ist. Mit anderen Worten: Wo der Pool vorher nur einen Bitcoin Block gelöst hat, da löst er zusätzlich nebenher noch einen oder mehrere Namecoin Blocks. Die Namecoin Blocks gibt es also quasi "gratis". In Zukunft werden weitere Blockchains nach dem gleichen Schema implementiert, sobald sie merged mining anbieten. Bis zum Start von merged mining gibt es allerdings "nur" Namecoins, da der Pool seinerzeit als Namecoin Server gestartet ist.

Es handelt sich um einen Propotional Pool. Ihr könnt Euch zwischen einem Mining Ingress Server in DE (beste Wahl in DE ^^) oder US entscheiden. Ansonsten gibt es das volle Wohlfühlprogramm mit E-Mailbenachrichtigung beim Minerausfall, Instant Payouts (mit 2% Gebühr) oder nächtliche Scheduled Payouts (mit nur 1% Gebühr), JSON Statistiken, etc. Die Gebühr (Fee) ist eine Auszahlungsgebühr. Sie wird also beim Abrufen der Coins fällig. Nur so kann ich unterschiedliche Konditionen anbieten. Die eingenommenen Transaktionsgebühren (des gelösten Blockes) werden auch an alle Miner ausgeschüttet.

Ich hatte bisher nicht die Zeit die Webseite zu übersetzen. Aber ich wollte Euch wissen lassen, dass ich auch deutschen Support bieten kann. In jedem Fall würde ich mich freuen einige von Euch begrüßen zu dürfen. In den nächsten Tagen wird es noch ein Ankündigung im Englischsprachigen Forum geben. Bis dahin könnt Ihr euch aber gerne schonmal häuslich niederlassen und mich mit eventuellen Fragen bombardieren  

Ich nutze mein Mining Rig momentan auch als Arbeitsrechner und Berlin ist leider sehr weit weg vom Rheinland. Aber die Idee finde ich total cool und unterstützenswert. Hast du Kontakt zu mehreren Betreibern? Vielleicht sogar Deutschlandweit? Wenn Euch da wirklich ein Open Source Modell vorschwebt (Im Sinne von einer Art "MiningRig / Servergenossenschaft") die sich eine Plattform "pachtet" oder mietet und gleich günstigen Strom vom Erzeuger bezieht, dann kann man da sicherlich ein tolles Projekt draus machen.

Also ich bin definitv Fan von derart dezentralen Serverknotenpunkten. Und ich muss auch gleich wieder los spinnen Wenn man irgendwann das ganze mittels Freifunk koppelt kann man unter den einzelnen Knoten ein Meshnetz aufbauen, und das ganz wird für noch viel mehr Projekte interessant. Also auf jeden Fall dran bleiben! Top Aktion! Und vor allem gleich Bescheid geben, wenn Ihr jemanden in NRW habt, der sowas anbietet 

it seems we finally agreed on a block for merged mining over at the NMC Forum. The block number for merged mining will be 19,200 (Namecoin block) which is less than 400 blocks away. At the current speed we will hit block 19200 at about mid september. I deployed the current NMC merged mining namecoind and bitcoind. But we are still running on testnet. However production MasterPool (https://www.masterpool.eu/merged) has already deployed the same versions and is running on NMC blockchain. With block 19200 the pool will automatically start mining BTC as well.

So this might be my last post on this thread. I want to thank all testers and want to invite you to join us on https://www.masterpool.eu/. However as soon as we have precompiled merged mining binaries of namecoind available I'll post a new thread for the production server. The alpha testserver will vanish sometime after merged mining startet. Thus if you want your Testnet BTC and/or NMC please withdraw them. All the other testnet coins will be transfered to testnet faucets.

I don't know if Freicoin ever will work on a large scale. But in fact no one knows since it has not been done before. In Germany I know about a few local clubs who have some sort of Gesells Freigeld and it seems people like it on a local scale. Furthermore I belong to the few people who are not interested in cryptocurrencies for making quick money. And I feel like we need to get this implemented just in order to see if it works. If it don't work on a global scale I guess there will be plenty of local adopters. Because as soon as freicoin is implemented we might see local clubs adopt this to get their Freigeld system online.

Added 2 BTC to the Bounty 

I really enjoy the insane mining rig pictures as well. But my wife would never allow me to have such things at home. Thus I needed a mining rig with a very high wife acceptance factor I really love the the old Chieftech Dragon Towers:



But in order to build a mining rig out of this case it needs some tuning  



At night and on cool days the Cape Cora HF is cooling three HD 5870 @900MHz with Memory underclocked to 195MHz and a Phenom X4 955 BE passively without problems. However the GPUs needed some tuning as well  





At day however there are three radiators who kick in to take care the system stays cool (one 120mm radiator at back and a dual 80mm radiator at front. Both hidden inside the case blowing the hot air out).

This systems makes 1.2 Ghash/s (each 5870 ist quite stable at about 404 MHash/s) My Mainboard is an ASRock 890GX Extreme4 which features an additional Radeon HD 4290 onboard GPU which is not capable of mining. But I use the onboard chip as primary GPU and thus are mining with all three 5870 GPUs at highest possible aggression level even if I'm using the PC for work, watching HD movies or playing not too current games without any performance issues.

The system runs stable even at 36 centigrade room temperature (the highest temperature so far). GPU temperature is even at such high room temperatures not higher than 65 centigrades. And the mining rig is really calm. If you don't know there is a PC running you wouldn't even notice it is running. Water cooling rocks!

A bit Off Topic, but I want to position this as public a possible:

I'm neither the developer, nor the inventor of Merged Mining.

I'm just a pool operator, who is eager to get MM into production state. I gathered information about MM at dot-bit wiki: http://dot-bit.org/MergedMining and implemented the first public merged mining pool. But nothing more.

Credits for Merged Mining go to:

• Mike Hearn (https://bitcointalk.org/index.php?action=profile;u=2700) for the technical fundamentals: https://en.bitcoin.it/wiki/Alternative_Chains
• vinced (http://dot-bit.org/forum/memberlist.php?mode=viewprofile&u=73) who implemented MM

I don't know where this rumours started and I truly hope, that I didn't say or write anything that led to the conclusion I might be the inventor of Merged Mining. But as I got two inquiries about merged mining today, suggesting I'm the inventor, I thought it'll be better to clearify this before rumours spread. I'm still answering questions about merged mining (as far as I'm able to do so) and compile information into the wiki article, but please give credits to the persons who deserve it!

I just deployed RC5 on alpha. Furthermore I deployed latest MasterPool Frontend. In the dashboard you can now find the new Scheduled Payout feature. This feature (if enabled and given you provided an address for each blockchain) will do automatic payouts every hour. Thus you can fire and forget your miners and test payouts very easily. All payouts (BTC and NMC) should work now (though they are not guaranteed) if you have at least a RC5 namecoind.

Please read the warning at: https://alpha.masterpool.eu/

Using rc.local you "fire-and-forget" the daemon. UNIX style is to have an init script which you can use in order to start, stop and restart daemons. Furthermore the init process will start the daemons for you if you linked the init script to the appropriate runlevel(s) and stops them properly if you reboot/halt the server. With this knowledge you should have a look at this thread:

http://bitcointalk.org/?topic=965.0

and adapt it to your needs. It should help you doing it the "right" way. Do the same for pushpoold. If you like you can tip the original author.

The pool has verified its first block. I resetted the balance of all users and thus dispossessed everybody From now on you should be able to withdraw namecoins. But remember, you have to use a modified client in order to receive those merged mining namecoins! (see above).

Please try to withdraw namecoins and transfer them for testing. If you don't have any use for them after testing it would be nice if you transfer them back to the pool. This will make it possible to have other users test transactions as well:

NMC: moVDDfgu7AXaTS35BWTkgy1Pkcu9WxTaQw

If you need a few merged mining namecoins just let me know your NMC address. I'll send you a few for testing.

Yes thank you very much. This is much appreciated. I'd like to generate at least 120 "fresh" blocks (with merged mining enabled). After that we get the first namecoins and can even test transactions. The more hashrate we have for testing the earlier we break even with testing. ATM we have about 50 percent of the blocks needed in order to get a block payed out.

Edit: Just realized this is the Bitcoin Forum. I'd like to announce, that we are now running on a patched namecoin version which includes proof of work in to the blockchain. As this is incompatible with the old testnet blockchain we splitted the "original" namecoin blockchain now having a separate "test testnet blockchain"   However to get namecoins payed out after the first block is confirmed you need a slightly modified namecoind:

https://github.com/nodemaster/namecoin

You might also want to check the alpha pool thread on namecoin forum: http://dot-bit.org/forum/viewtopic.php?p=1565#p1565 as well as the dev thread: http://dot-bit.org/forum/viewtopic.php?f=5&t=269

Da mich über Nacht mehrere PM mit fast gleichlautenden Fragen erreicht haben antworte ich mal hier für alle  

• Bezüglich der Blockchain gilt bei namecoin das gleiche wie für bitcoin. Sie muss vollständig heruntergeladen sein um Einsatzbereit zu sein. Insbesondere für Solo Mining ist das wichtig. Ermitteln kann man dies mittels namecoind getinfo. Aktuell sind wir bei block 18407
• Ob Ihr genügend connections habt ermittelt Ihr ebenfalls mit namecoind getinfo, unter connections. Ohne UPNP/Portfreigabe habt Ihr hier maximal 8. Je mehr umso besser natürlich. Tipp: namecoind mit Schalter -upnp starten, falls Euer Router dies unterstützt.
• Namecoin Addressen verifiziert Ihr auf der Shell mit namecoind validateaddress ADDRESSE.
• Beim Solo Mining bekommt man vom namecoind keine Difficulty 1 shares, sondern shares mit der entsprechenden Difficulty. Dies unterscheided sich von Pools, die in der Regel Shares mit einer difficulty von eins herausgeben um so die Aufgaben aufzuteilen. Dadurch bedingt bekommt Ihr bei den meisten Minern auch nicht angezeigt, dass Ihr stetig einen Share übertragen habt. Dies geschieht nur und einmalig, sobald Ihr einen Block gefunden habt.Soweit ich weis zeigt der GUIMiner jedoch an, was wäre, wenn Ihr eine Difficulty von eins hättet (also eine Art Poolemulation).
• Das Leute beim Bitparking Exchange Addressen jeweils der falschen Blockchain eintragen ist leider häufig der Fall und ich denke hier muss doublec (Der Operator) auch noch dringend nachbessern. Falls es Euch passiert ist, sind eure NMC/BTC jedoch noch nicht unbedingt unwiderbringlich verloren. Sie spuken in der jeweils falschen Blockchain herum und werden rejected. Man kann sie jedoch durch Verbindung des "richtigen" Clients mit dem "falschen" P2P-Netz wieder recovern. Ich habe es bisher nicht gemacht. Aber triggert mal doublec in diesem Thread an: http://dot-bit.org/forum/viewtopic.php?f=7&t=240

Ihr scheint alle ein inoffizielles namecoin GUI zu verwenden. Dies ist mir leider nicht bekannt. Könnt Ihr mich mal kurz dahin stupsen, wo ich den finde?

Happy Mining!

Ich wollte nur mal kurz in den Raum werfen, dass der Pool von mir betrieben wird (sowohl der alpha Merged Mining Testpool, als auch der Stable NMC Pool). Ich bin momentan häufiger im Namecoin Forum unterwegs, weil wir Merged Mining durchtesten (aktuell RC3). Wenn Ihr allerdings deutschen Support benötigt, dann triggert mich einfach an. Wir freuen uns über jeden, der Interesse an Namecoins und Merged Mining hat. Falls Ihr also fragen dazu habt, lasst es mich wissen.

Momentan ist im Release Candidate Block 24000 eingetragen als Übergang zum Merged Mining. aufgrund der Flaute diskutieren wir im Forum aber bereits einen früheren Zeitpunkt. Es hängt jedoch von den Ergebnissen der Tests ab, ob wir früher starten können.