This problem just started recently - used to work a few months ago, now I'm trying to figure out what changed. Using proftpd, with MasqueradeAddress for PASV support. I looked at my NAT router (SMC Barricade), it looks fine. SSH from external sites work. FTP from localhost works. FTP from external sites fails. I can see that the NAT router is working fine - I did a telnet to port 21, here's what I got: telnet hostname.dynds.... 21 Trying <ip address>... Connected to hostname.dynds.... (<ip address>). Escape character is '^]'. 500 Sorry, no server available to handle request on 10.0.0.15 Connection closed by foreign host. 10.0.0.15 is the IP address of the host that is running the SSH, FTP, etc servers. Clearly there is a FTP server there since doing a "ftp localhost" works on it. I am stumped, I ran proftpd in debug mode, and when I did a remote connect, I saw these lines in the output:bombay5.aczoom.home - ROOT PRIVS at main.c:1162 hostname - RELINQUISH PRIVS at main.c:1166 hostname - FS: using system lstat() hostname - FS: using system lstat() hostname - FS: using system lstat() That is not very helpful, so if anyone has any ideas where to start debugging, let me know. I captured packets using Ethereal, and just before the "Sorry, no server" message, I see this: DNS Standard Query PTR 15.0.0.10.in-addr.arpa with a respone: DNS No such name and then the next packet is the 500 Sorry, no server available to handle request on 10.0.0.15 This is probably the crux of the issue - not sure why my Fedora FC3 system is doing a DNS query for 10.0.0.15 - that is a local, private address. Any ideas on what to try next?
