I have proFTPd setup on an Ubuntu server with 12 network interfaces, each one connected to a separate DSL line. The server binds to the 12 interfaces fine but has trouble taking connections on the 11 other than the first interface.

- Each DSL line has a dynamic IP and is mapped to a DynDNS name.
- Each interface is behind a NAT in the DSL router. (An incoming connection is able to get to the server so the incoming NAT is working fine)
- All relevant ports are opened for FTP on each router and forwarded to the appropriate internal IP
- Each interface in proFTPd is setup to use a DNS service to lookup the interface IP for PASV transfers. Each interface has a different DNS name
- All interfaces are visible and enabled in the interface list
- Each of the interfaces has an internal IP of 192.168.n.11 and the router has an IP of 192.168.n.1.
- The server is running Ubuntu Server 6.10 with no firewall software

With these routes I was able to ftp to each interface independently and get directory listings. I am also able to upload data from the client to each of the 12 interfaces.

ip route add 192.168.2.0/24 dev eth2 src 192.168.2.11 table r2
ip route add 192.168.3.0/24 dev eth3 src 192.168.3.11 table r3
...
ip route add 192.168.12.0/24 dev eth12 src 192.168.12.11 table r12

ip rule add from 192.168.2.11 table r2
ip rule add from 192.168.3.11 table r3
...
ip rule add from 192.168.12.11 table r12

ip route add default via 192.168.2.1 table r2
ip route add default via 192.168.3.1 table r3
...
ip route add default via 192.168.12.1 table r12

The strange part is that I am actually able to download in ascii mode but not in binary mode from any of the interfaces other than the default interface (eth1)

I also tried loading ip_conntrack and ip_conntrack_ftp but that did not work. I also added the following iptable entries but they didn't help either.

iptables -A INPUT -i eth2 -p tcp --sport 1024: --dport 1024: -d 192.168.2.11 -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A OUTPUT -o eth2 -p tcp --sport 1024: --dport 1024: -s 192.168.2.11 -m state --state ESTABLISHED -j ACCEPT

So now I am able to do the following using PASSIVE mode
- Upload from Client -> Server in ASCII and BINARY mode
- Download from Server -> Client in ASCII mode only.

I have also tried several ftp clients.

Any ideas why BINARY mode is not working for downloads?

Thanks

Any routing or ftp experts out there who can help with this problem?

Your advice will be greatly appreciated.

Thanks in advance,

Mediaeast

I have run Wireshark to trace the communication in the server during ASCII and Binary transfers. THere does not seem to be any significant difference from the FTP server point of view.

Does anyone know what the difference might be from a routing point of view between ASCII and Binary ftp transfers? Both are running in passive ftp mode.

Thanks

hi,

what are you trying to do exactly with putting 3x4ports NIC?
( i wished i have that intel NIC )

have you try to change the client request mode to binary?
AFAIK - if you've set up your routing,NAT etc correctly - there is no problem with routing.
check your proftpd config again - one more..

HTH.