Electrum - RBF - Error Message Query

[ragnar dannesk gold]

Using Electrum RBF, I attempted to increase a transaction fee (by an arbitrary amount) to learn the process.



This fee that Electrum selects ( 1.5sat/byte over the previous 1sat/byte) appears to be fine for my learning (I'm happy to wait or have it fall from the mempool eventually).

But when trying to broadcast the transaction the following comes up:



I am using my own node so it wasn't the server. So I was trying to think why this would be. I tried a variety of different unconfirmed transactions before trying one at 2 sat/byte. Which worked.

Was the error in actual fact just trying to increase the fee by too small an amount?

If so, I believe changing the error message to reflect this (or a message suggesting minimum increase/multiple) would be helpful.


Edit - Reading through BIP125 I see the following which probably explains why my transaction required a higher fee-bump:

4. The replacement transaction must also pay for its own bandwidth at or above the rate set by the node's minimum relay fee setting. For example, if the minimum relay fee is 1 satoshi/byte and the replacement transaction is 500 bytes total, then the replacement must pay a fee at least 500 satoshis higher than the sum of the originals.

Maybe the suggested minimum RBF fee suggested/allowed by Electrum could reflect this rule (if that is indeed the current network rule).

So my 316 byte transaction required a fee bump of at least 316 bytes to be accepted by (most) of the network). <- Maybe an explanation of this requirement could be included in the error message?

[djhomeschool]

I think you are connection to a phishing server.....

Try to connect to another server (Tools - Network - Server) and right click on a server and select "Use this server". One of the servers i always use is "e2.keff.org", see if that one is in your list.

Let us know if this helped.

[ragnar dannesk gold]

I think you are connection to a phishing server.....

Try to connect to another server (Tools - Network - Server) and right click on a server and select "Use this server". One of the servers i always use is "e2.keff.org", see if that one is in your list.

Let us know if this helped.

Hi djhomeschool,

Thanks for taking the time to reply.

I am most definitely not connected to a phishing server as I am connecting to my own node via Electrum Personal Server. I have figured out (I believe) the issue, and am suggesting an improvement to help others who come across this error


TLDR: RBF has a rule that requires your RBF fee bump to be at least the size of your transaction in bytes above the original fee. (So a transaction that's 225 bytes, paying 1,000 sats can only be bumped by 225 sats or more).

This isn't reflected in Electrum, and took me some research to figure out, so I am suggesting the error message be updated to better reflect it (and potentially the algorithm for suggesting the fee bump too).

[djhomeschool]

I think you are connection to a phishing server.....

Try to connect to another server (Tools - Network - Server) and right click on a server and select "Use this server". One of the servers i always use is "e2.keff.org", see if that one is in your list.

Let us know if this helped.

Hi djhomeschool,

Thanks for taking the time to reply.

I am most definitely not connected to a phishing server as I am connecting to my own node via Electrum Personal Server. I have figured out (I believe) the issue, and am suggesting an improvement to help others who come across this error


TLDR: RBF has a rule that requires your RBF fee bump to be at least the size of your transaction in bytes above the original fee. (So a transaction that's 225 bytes, paying 1,000 sats can only be bumped by 225 sats or more).

This isn't reflected in Electrum, and took me some research to figure out, so I am suggesting the error message be updated to better reflect it (and potentially the algorithm for suggesting the fee bump too).

Good find!

Glad you got this solved, maybe @ThomasV will read this and take notice.

[ragnar dannesk gold]

Further thinking about this rule:

https://github.com/bitcoin/bips/blob/master/bip-0125.mediawiki

4. The replacement transaction must also pay for its own bandwidth at or above the rate set by the node's minimum relay fee setting. For example, if the minimum relay fee is 1 satoshi/byte and the replacement transaction is 500 bytes total, then the replacement must pay a fee at least 500 satoshis higher than the sum of the originals.

The only time this error would ever occur, is when the original fee was <2 sat per byte.

Electrum appears to suggest increasing the fee by 1.5x, and this rule would always provide a high enough bump if the original fee were 2 or more sat/byte.

Example: 225 byte transaction @ 2sat/byte = 450 sat transaction
RBF Electrum - 1.5x fee = 675 sats (225 sats higher than the original fee, thus paying for its own bandwidth as per rule 4).  <- Accepted

Example 225 byte transaction @ 1sat/byte = 225 sat transaction
RBF Electrum - 1.5x fee = 338 sats (113 sats higher than the original fee, thus not paying its own bandwidth as per rule 4). <- Rejected

Example 225 byte transaction @ 10sat/byte = 2250 sat transaction
RBF Electrum - 1.5x fee = 3378 sats (1,126 sats higher than the original fee, thus paying its own bandwidth as per rule 4). <- Accepted


A simple fix would be to suggest the bump as: whichever is the higher of either [1.5x the original fee] or [an increase of sats equal to the bytes of the new transaction].

[Abdussamad]

you should file an issue on github because this looks like a bug

[ragnar dannesk gold]

Having read through some of the recent Electrum release notes, I think this issue may have been fixed, although I haven't tested it myself, and reading the code/github is beyond my ability

[nc50lc]

Having read through some of the recent Electrum release notes, I think this issue may have been fixed, although I haven't tested it myself, and reading the code/github is beyond my ability

If you used the latest version at the timestamp of the OP which is: 3.3.6;
there were only two updates that occurred after it that have RBF improvements, but I can't see any minimum recommended bump fee update.

In the latest: Just two [solved] crash reports caused by errors. (#5502 and #5483)
In the later one: Changed/Prioritize another way to add the extra fee. (from deducted from the outputs' amount or change->to add more input(s) if needed)-edit-
Since it's almost 3months, I've opened a new issue: #5636
Let's see if they will link a duplicate.