Topic: fully-featured DNS server question

[kruhm]

I want to use my SME as my local DNS server.

The problem is when my SME has no master DNS set (self-pointing), I can't surf the internet. My lan gets flooded with DNS requests from my SME. I suppose because of the RBL lookups.

When I type in the ISP DNS, the problem disappears. But doesn't this mean that reverse lookups for the lan won't work correctly?

Server-only
v6.0.1-01

[CharlieBrady]

The problem is when my SME (server-only) has no master DNS set (self-pointing), I can't surf the internet.

Three things to check:

- Is the gateway setting on the server correct? If the server can't get to the Internet, it's not going to be able to resolve names.
- Do the clients have the correct DNS settings, and correct gateway address. They'll usually get that via DHCP, but you haven't told us how you have DHCP set up.

My lan gets flooded with DNS requests from my SME.

What evidence leads you to concluse that?

 But doesn't this mean that reverse lookups for the lan won't work correctly?

Probably.

[kruhm]

Is the gateway setting on the server correct?
The gateway settings on the server are correct. The clients can sometimes resolve addresses and pull up half the page. But eventually times out, leaving out pics etc.

- Do the clients have the correct DNS settings, and correct gateway address.
Yes. It happens no matter if the clients get their address from a W2K_server or a SME. I've manually changed the dns settings as well. Still the same, as long as the sme is plugged in the lan.

What evidence leads you to concluse that?
Packet sniffer shows that in just 5 minutes, more than 15,000 dns packets (about 40 requests a second). Below is about a thrid of a second:

17   sme   IP-192.203.230.10   92   07:11:37.389180   UDP DNS   56.223.26.72.dnsbl.sorbs.net.
18   sme   IP-192.58.128.30   103   07:11:37.478994   UDP DNS   7.180.63.66.postmaster.rfc-ignorant.org.
19   sme   IP-192.36.148.17   100   07:11:37.479071   UDP DNS   120.45.69.202.whois.rfc-ignorant.org.
20   sme   IP-193.0.14.129   94   07:11:37.518976   UDP DNS   87.231.205.211.dnsbl.sorbs.net.
21   sme   IP-198.41.0.4   99   07:11:37.519052   UDP DNS   36.167.86.64.abuse.rfc-ignorant.org.
22   sme   IP-202.12.27.33   92   07:11:37.519141   UDP DNS   155.229.154.218.in-addr.arpa.
23   sme   IP-198.41.0.4   100   07:11:37.558965   UDP DNS   139.183.35.80.abuse.rfc-ignorant.org.
24   sme   IP-198.32.64.12   100   07:11:37.559041   UDP DNS   127.216.121.219.sbl-xbl.spamhaus.org.
25   sme   IP-192.5.5.241   97   07:11:37.618950   UDP DNS   225.1.5.72.whois.rfc-ignorant.org.
26   sme   IP-198.41.0.4   92   07:11:37.619020   UDP DNS   182.4.69.193.relays.ordb.org.
27   sme   IP-209.204.159.15   98   07:11:37.619115   UDP DNS   7.180.63.66.abuse.rfc-ignorant.org.
28   sme   IP-210.180.98.86   92   07:11:37.619205   UDP DNS   183.166.232.218.in-addr.arpa.
29   sme   IP-192.36.148.17   93   07:11:37.619296   UDP DNS   148.45.38.207.relays.ordb.org.
30   sme   IP-192.203.230.10   101   07:11:37.619392   UDP DNS   153.83.253.203.abuse.rfc-ignorant.org.
31   sme   IP-208.201.249.238   103   07:11:37.658938   UDP DNS   7.180.63.66.postmaster.rfc-ignorant.org.

[CharlieBrady]

What evidence leads you to conclude that?
Packet sniffer shows that in just 5 minutes, more than 15,000 dns packets (about 40 requests a second). Below is about a thrid of a second:
...

[/quote]

40 DNS requests a second is not "flooding" your LAN. That just indicates you are receiving mail, and doing RBL lookups.

What version of SME do you have? Have you applied any updates (e.g. e-smith-dnscache-0.3.0-04.noarch.rpm)?

[kruhm]

Server-only
v6.0.1-01
Unofficial Update script
e-smith-dnscache-0.2.0-01
e-smith-dhcpmanager-1.5-1
sme-dhcp-dns-1.0-1

FYI -the dns packets only show when the SME is self-pointing. When the dns points externally, they don't show.