[clue-tech] Network Woes
Todd A. Gibson
tgibson at augustcouncil.com
Mon Jun 19 22:00:45 MDT 2006
On Mon, Jun 19, 2006 at 04:52:30PM -0600, Jim Ockers wrote:
> Todd,
>
> > Setup: Everything in the house is connected to a switch. A DSL modem
> > and a server have fixed LAN IP addresses. The other computers receive
> > DHCP services from the server (DHCP server services are turned off on
> > the DSL modem).
> >
> > Symptoms:
> > I lose the ability to make new connections through the DSL modem
> > (either into or out of my server). New connections include Web
> > queries, ssh, telnet, ftp, etc. Also during this time some LAN
> > traffic is hamstrung.
> >
> > Examples:
> > local_one$ ping local_two #works OK
> > local_one$ ssh local_two # 15-30 second delay before prompted for password
> > local_one$ ssh 192.168.1.246 # prompted for password immediately
>
> Please run ssh inside of strace and see what system call is waiting
> for a return code.
When DSL is down, ssh it polls 192.168.1.2 which is the server running DNS. Then it
polls the secondary DNSs which are on the other side of the DSL modem.
After a few more polls it looks like it connects with my local DNS
and continues on.
When DSL is up and running, it immediately connects with the local
server and is off and running. I don't think any of this addresses
my DSL woes, but does it indicate an obvious misconfiguration of my
DNS server?
Below are the two relevant excerpts:
######################################################################
################# When DSL is DOWN ##################################
######################################################################
open("/etc/resolv.conf", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=135, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40017000
read(3, "; generated by /sbin/dhclient-sc"..., 4096) = 135
read(3, "", 4096) = 0
close(3) = 0
munmap(0x40017000, 4096) = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
connect(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.1.2")}, 28) = 0
send(3, "\204c\1\0\0\1\0\0\0\0\0\0\10drhoovey\raugustcoun"..., 44, 0) = 44
gettimeofday({1150773628, 893902}, NULL) = 0
poll([{fd=3, events=POLLIN, revents=POLLIN}], 1, 5000) = 1
ioctl(3, FIONREAD, [99]) = 0
recvfrom(3, "\204c\205\200\0\1\0\0\0\1\0\0\10drhoovey\raugustcoun"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.1.2")}, [16]) = 99
close(3) = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
connect(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.1.2")}, 28) = 0
send(3, "\204d\1\0\0\1\0\0\0\0\0\0\10drhoovey\0\0\34\0\1", 26, 0) = 26
gettimeofday({1150773628, 894869}, NULL) = 0
poll(
******************** HANG *****************************
[{fd=3, events=POLLIN}], 1, 5000) = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4
connect(4, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("206.124.0.254")}, 28) = 0
send(4, "\204d\1\0\0\1\0\0\0\0\0\0\10drhoovey\0\0\34\0\1", 26, 0) = 26
gettimeofday({1150773633, 904617}, NULL) = 0
poll(
******************** HANG *****************************
[{fd=4, events=POLLIN}], 1, 3000) = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 5
connect(5, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("206.124.1.254")}, 28) = 0
send(5, "\204d\1\0\0\1\0\0\0\0\0\0\10drhoovey\0\0\34\0\1", 26, 0) = 26
gettimeofday({1150773636, 915041}, NULL) = 0
poll(
******************** HANG *****************************
[{fd=5, events=POLLIN}], 1, 6000) = 0
send(3, "\204d\1\0\0\1\0\0\0\0\0\0\10drhoovey\0\0\34\0\1", 26, 0) = 26
gettimeofday({1150773642, 925651}, NULL) = 0
poll(
******************** HANG *****************************
[{fd=3, events=POLLIN}], 1, 5000) = 0
send(4, "\204d\1\0\0\1\0\0\0\0\0\0\10drhoovey\0\0\34\0\1", 26, 0) = 26
gettimeofday({1150773647, 936178}, NULL) = 0
poll(
******************** HANG *****************************
[{fd=4, events=POLLIN}], 1, 3000) = 0
send(5, "\204d\1\0\0\1\0\0\0\0\0\0\10drhoovey\0\0\34\0\1", 26, 0) = 26
gettimeofday({1150773650, 946592}, NULL) = 0
poll(
******************** HANG *****************************
[{fd=5, events=POLLIN}], 1, 6000) = 0
close(3) = 0
close(4) = 0
close(5) = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
connect(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.1.2")}, 28) = 0
send(3, "\204e\1\0\0\1\0\0\0\0\0\0\10drhoovey\raugustcoun"..., 44, 0) = 44
gettimeofday({1150773656, 958314}, NULL) = 0
poll([{fd=3, events=POLLIN, revents=POLLIN}], 1, 5000) = 1
ioctl(3, FIONREAD, [98]) = 0
recvfrom(3, "\204e\205\200\0\1\0\1\0\1\0\1\10drhoovey\raugustcoun"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.1.2")}, [16]) = 98
close(3) = 0
######################################################################
################# When DSL is UP ##################################
######################################################################
######################################################################
open("/etc/resolv.conf", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=135, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40017000
read(3, "; generated by /sbin/dhclient-sc"..., 4096) = 135
read(3, "", 4096) = 0
close(3) = 0
munmap(0x40017000, 4096) = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
connect(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.1.2")}, 28) = 0
send(3, "\335\\\1\0\0\1\0\0\0\0\0\0\10drhoovey\raugustcoun"..., 44, 0) = 44
gettimeofday({1150774664, 548416}, NULL) = 0
poll([{fd=3, events=POLLIN, revents=POLLIN}], 1, 5000) = 1
ioctl(3, FIONREAD, [99]) = 0
recvfrom(3, "\335\\\205\200\0\1\0\0\0\1\0\0\10drhoovey\raugustcoun"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.1.2")}, [16]) = 99
close(3) = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
connect(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.1.2")}, 28) = 0
send(3, "\335]\1\0\0\1\0\0\0\0\0\0\10drhoovey\0\0\34\0\1", 26, 0) = 26
gettimeofday({1150774664, 549622}, NULL) = 0
poll([{fd=3, events=POLLIN, revents=POLLIN}], 1, 5000) = 1
ioctl(3, FIONREAD, [101]) = 0
recvfrom(3, "\335]\201\203\0\1\0\0\0\1\0\0\10drhoovey\0\0\34\0\1\0\0"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.1.2")}, [16]) = 101
close(3) = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
connect(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.1.2")}, 28) = 0
send(3, "\335^\1\0\0\1\0\0\0\0\0\0\10drhoovey\raugustcoun"..., 44, 0) = 44
gettimeofday({1150774664, 633516}, NULL) = 0
poll([{fd=3, events=POLLIN, revents=POLLIN}], 1, 5000) = 1
ioctl(3, FIONREAD, [98]) = 0
recvfrom(3, "\335^\205\200\0\1\0\1\0\1\0\1\10drhoovey\raugustcoun"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.1.2")}, [16]) = 98
close(3) = 0
socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3
connect(3, {sa_family=AF_INET, sin_port=htons(22), sin_addr=inet_addr("192.168.1.235")}, 16) = 0
setsockopt(3, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0
brk(0) = 0x808d000
brk(0x808e000) = 0x808e000
brk(0) = 0x808e000
brk(0x808f000) = 0x808f000
etc.
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