ssh connects to originating host
Geoffrey Leach
geoff at hughes.net
Tue May 12 20:37:49 UTC 2009
On 05/12/2009 01:20:03 PM, Shashank wrote:
> Can you provide the output of following commands on both A and B?
>
> netstat -nr
> traceroute host (A when logged in to B and viceversa)
> arp -a ( on both A and B)
> ifconfig (on A) eliminate the public IP/GATEway before you post it
> here.
>
>
> You may not have the correct path to the network (private) .
>
Please see reply at end
>
>
> On Tue, May 12, 2009 at 2:29 PM, Geoffrey Leach <geoff at hughes.net>
> wrote:
> > On 05/12/2009 11:12:42 AM, Christopher K. Johnson wrote:
> >> Geoffrey Leach wrote:
> >> > Two systems A and B, connected via wireless. A and B both have
> the
> >> same
> >> > /etc/hosts. Connecting from B to A, "ssh A", works fine. However
> on
> >> A,
> >> > "ssh B" logs me into A. This used to work fine; the only clue I
> >> have
> >> is
> >> > that ssh did not like the stored RSA key. I let it fix it, and
> >> that's
> >> > when the trouble started. Rebooting A did not fix, nor did
> removing
> >> the
> >> > saved key and repeating.
> >> >
> >> > Any suggestions?
> >> >
> >> > Thanks.
> >> >
> >> >
> >> >
> >> My best guess:
> >> The stored key issue was symptomatic of the problem resolving host
> to
> >> ip
> >> address incorrectly.
> >>
> >> There are three things to check:
> >> 1) Logged on at host A, what does 'host B' command return for
> >> information? Is it the correct address for B? If the wrong
> address
> >> then you need to research whether your dns server or an /etc/hosts
> >> entry
> >> is the cause.
> >
> > Keeping in mind that this all worked previously ....
> > The 'domain' is mtranch.com. Quotes because its not a registered
> domain
> > Host A is mtranch.mtranch.com, host B is pvr.mtranch.com
> >
> > host B on A:
> > root at mtranch[9]->host pvr
> > pvr.mtranch.com has address 63.251.179.5
> > Host pvr.mtranch.com not found: 3(NXDOMAIN)
> > Host pvr.mtranch.com not found: 3(NXDOMAIN)
> >
> > I believe that 63.251.179.5 is my ISP's (I'm on satelite with a
> dynamic
> > IP address) DNS server.
> >
> > root at mtranch[16]->ping pvr
> > PING pvr.mtranch.com (192.168.10.4) 56(84) bytes of data.
> >
> > That's the IP address that's in /etc/hosts. Other direction also
> works.
> >
> > If I go over to pvr, I can ssh to mtranch. However, if I try to NFS
> > mount directories on mtranch (A) to pvr (B) that fails with
> > "Permission Denied". Again, worked fine yesterday.
> >
> >> 2) Whatever user you do this as on host A, is there a ~/.ssh/
> config
> >> file? And if so, does it have a stanza that defines how to
> contact
> >> host
> >> B, but do so with the wrong name or ip address?
> >
> > There's no ~/.ssh/config, and /etc/ssh/ssh_config is the stock
> version
> > from Fedora 10
> >
> >> 3) It is also possible, but less likely, that on host A you have
> dnat
> >> rules in iptables causing the endpoint for that ssh tcp connection
> to
> >> be
> >> changed to a local host based address.
> >
> > I disabled the firewall (I'm using Firestarter); no change in
> behavior
>
On 'A' -- 192.168.10.3 mtranchw.mtranch.com mtranchw is the
wireless
connection on A.
root at mtranch[19]->netstat -nr
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window
irtt Iface
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0
0 eth0
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0
0 wlan0
0.0.0.0 192.168.10.1 0.0.0.0 UG 0 0
0 eth0
root at mtranch[20]->traceroute pvr
traceroute to pvr (192.168.10.4), 30 hops max, 60 byte packets
1 pvr.mtranch.com (192.168.10.4) 0.073 ms 0.036 ms 0.033 ms
root at mtranch[21]->arp -a
mtranchw.mtranch.com (192.168.10.3) at 00:1a:ef:03:03:e3 [ether] on
eth0
? (192.168.10.1) at 00:18:4d:88:55:c2 [ether] on eth0
root at mtranch[22]->ifconfig
eth0 Link encap:Ethernet HWaddr 00:18:F3:98:CD:0B
inet addr:192.168.10.2 Bcast:192.168.10.255
Mask:255.255.255.0
inet6 addr: fe80::218:f3ff:fe98:cd0b/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:8707 errors:0 dropped:0 overruns:0 frame:0
TX packets:7352 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:6635268 (6.3 MiB) TX bytes:714646 (697.8 KiB)
Interrupt:19 Base address:0x400
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:1010 errors:0 dropped:0 overruns:0 frame:0
TX packets:1010 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:104950 (102.4 KiB) TX bytes:104950 (102.4 KiB)
wlan0 Link encap:Ethernet HWaddr 00:19:D2:2D:F2:76
inet addr:192.168.10.4 Bcast:192.168.10.255
Mask:255.255.255.0
inet6 addr: fe80::219:d2ff:fe2d:f276/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:91 errors:0 dropped:0 overruns:0 frame:0
TX packets:10 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:26284 (25.6 KiB) TX bytes:1512 (1.4 KiB)
wmaster0 Link encap:UNSPEC HWaddr 00-19-D2-2D-F2-76-
F4-9F-00-00-00-00-00-00-00-00
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
On 'B'
root at pvr[5]->netstat -nr
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window
irtt Iface
192.168.20.0 0.0.0.0 255.255.255.0 U 0 0
0 eth0
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0
0 wlan0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0
0 eth0
0.0.0.0 192.168.10.1 0.0.0.0 UG 0 0
0 wlan0
root at pvr[6]->traceroute mtranch
traceroute to mtranch (192.168.10.2), 30 hops max, 60 byte packets
1 mtranch.mtranch.com (192.168.10.2) 1.604 ms 1.810 ms 2.533 ms
root at pvr[7]->arp -a
mtranch.mtranch.com (192.168.10.2) at 00:18:f3:98:cd:0b [ether] on
wlan0
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