[SOLVED] Firebird 3. Connection rejected by remote interface lazarus / 16-Databases ---------------------------------------------------------------------- axline · 2020-12-20 04:25 There are two PCs with Windows 10 x64 and Firebird 3.0.7 x64. The Firebird versions are identical. One of the PCs has a sample database. I can connect to it locally with no issues by using 'localhost/3050:. Whenever I try to connect to this database (IP_address/3050:) from the other PC over the internet I get the 'connection rejected by remote interface' error. This error means that connection to the remote server had been established  and (for whatever reason) closed by the remote service_mgr. I've tested the TCP connection via telnet and nmap - no problem, the port is open and the connection  id successful. Usually such thing happens when versions or types (32-64) differ between the server and the client. In my case, there are two identical(!) servers installed on both machines. And all traces of any former installations (fbclient.dll, gds32.dll, firebird.conf) have been removed. Has anybody dealt with such thing? What else could be wrong? ---------------------------------------------------------------------- delphi2pk · 2020-12-28 09:27 I have also face this problem but resolved now. Here are some reasones: 1. Windows 10 may be blocking 3050 port (on server side). 2. Both interbase & firebird are installed on server computer. 3. fbclient.dll is older on client computer. 4. Database may be created in fb 2.5 ---------------------------------------------------------------------- avra · 2020-12-29 08:56 Quote from: axline on December 20, 2020, 05:25:40 amWhat else could be wrong?Normally you do not need to declare port 3050 in network connection string, but you need to set firewall exception for that port (or disable firewall temporary on both machines for a test). Try iSql command line tool and see if it shows more descriptive error messages. You can also try some GUI client you're familiar with. You could also try to temporary completely open network access to that file and see if that helped. https://www.firebirdsql.org/pdfmanual/html/isql-connect-database.html http://www.firebirdfaq.org/faq252/ https://www.experts-exchange.com/questions/23059151/Networking- Firebird-with-mapped-drive.html ---------------------------------------------------------------------- axline · 2021-01-17 09:09 Thanks for the comments delphi2pk, avra! I found the problem, though it was well hidden. The problem was with the network. There was a firewall somewhere between my machines (on one of the providers' side) which messed up the trafic. Took me quite a while (and lots of system tweaks on both of the PCs) to figure it out So I just moved the database to a cloud Linux server directly exposed to the internet...