05 Networking and DNS

Networking and DNS

network_card = a2065 gives the Zorro II LANCE card, the only NIC AMIX supports out of the box. FS-UAE emits a2065=slirp; confirm from the log:

A2065: 'slirp' 00:00:00:32:33:34

SLIRP is user-mode NAT: guest 10.0.2.15, gateway 10.0.2.2 (the Mac), DNS 10.0.2.3.

Interface

The interface is aen0, not le0 or en0. The 2.1 installer never asks for a netmask, so it must be configured by hand:

ifconfig aen0 10.0.2.15 netmask 255.255.255.0 up

The default route needs a trailing metric or the command is rejected:

/usr/sbin/route add default 10.0.2.2 1

Make both permanent in /etc/inet/rc.inet.

DNS

A DNS bundle is published on the wiki as amix_dns.zip (https://www.amigaunix.com/lib/exe/fetch.php/scripts_configs:amix_dns.zip). It sets up a local named forwarding to the SLIRP resolver, with /etc/resolv.conf pointing at nameserver 127.0.0.1.

Two fixes were needed before it would load — both findings from this build, not documented upstream:

• The SOA records lack the RNAME field (@ IN SOA 127.0.0.1. (), which a 1992 BIND rejects as a database format error.
• named.root carries AAAA records that BIND 4 cannot parse.

Keep the domain as nodomain. Otherwise lookups get the domain appended and ping breaks.

Inbound connections do not work on macOS

uae_a2065 = slirp_inbound opens a fixed set of host ports — 21–23 and 80. All are privileged, and FS-UAE runs unprivileged, so none can be bound. Verified with the guest fully booted and A2065: 'slirp_inbound' in the log: lsof -nP -iTCP -sTCP:LISTEN -p <pid> shows no listeners at all.

uae_slirp_redir and uae_slirp_ports exist and the core accepts them, but it accepts the option name without validating the value, so a result: 1 in the log proves nothing.

Outbound is unrestricted, so the way in is a reverse tunnel opened from AMIX, with Remote Login enabled on the Mac:

# on AMIX
ssh -R 2222:10.0.2.15:22 user@10.0.2.2
# then, from any Mac terminal, while that session stays open
ssh -p 2222 root@localhost

OpenSSH 3.9 offers only SHA-1 key exchange and ssh-rsa/ssh-dss host keys, all disabled by default in modern OpenSSH, so the Mac's /etc/ssh/sshd_config needs them re-enabled:

KexAlgorithms +diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1
HostkeyAlgorithms +ssh-rsa,ssh-dss
PubkeyAcceptedAlgorithms +ssh-rsa
Ciphers +aes128-cbc,3des-cbc
MACs +hmac-sha1

This weakens your SSH server for every client that connects to it, not just the emulator. SHA-1 key exchange and ssh-rsa are disabled by default in modern OpenSSH for good reasons. Scope it to the emulator's subnet:

Match Address 10.0.2.0/24
    KexAlgorithms +diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1
    HostkeyAlgorithms +ssh-rsa,ssh-dss

or revert it when you are done. Do not apply it globally on any machine reachable from a network you do not control.