two different approaches on the same problem

Let's presume your isp had the following config on your its side:

interface FastEthernet0/8
description Link to Dan - 1M
switchport access vlan 634
switchport trunk encapsulation dot1q
switchport trunk native vlan 635
switchport trunk allowed vlan 2,635
switchport mode trunk
no cdp enable
spanning-tree portfast
spanning-tree bpdufilter enable
spanning-tree bpduguard enable
spanning-tree guard none
service-policy input dan-1024

Why is it trunk? Because in between this switch and myself there is a radio bridge which is currently using vlan2 (for monitoring purpose). All of the sudden this config stops working after an IOS upgrade (says my ISP). (I was accessing vlan 635 on my side : switchport access vlan 634).

Since it was unlikely for my ISP to solve the problem (i don't know exactly what was wrong, they did not know either), here's the two approaches i found for this:

I had a 1800router with a NM8-ESW card

1. moved the cable from the radio unit to the NM-8ESW interface, put one of the fast
interfaces (fe0/0/1) to trunk mode, created vlan 634 (corresponding to
my vlan in the isp network), and after this changed the source
interface for tunnel1 from fast0/1 to vlan634 (which i configured with
ip address x.y.z.6/30). Was working, but had to try the next thing as well (see 2.)

2. put the cable from the radio unit back to fast0/1 , created a subinterface
on this (fast0/1.1) , assigned x.y.z.6/30 and encapsulation dot1q
634. Working again. Moved tunnel source to fa0/1.1

My relevant config:

ip sla monitor 1
type echo protocol ipIcmpEcho z.g.h.3
frequency 5
ip sla monitor schedule 1 life forever start-time now
ip sla monitor 2
type echo protocol ipIcmpEcho h.k.l.2
frequency 5
ip sla monitor schedule 2 life forever start-time now

track 123 rtr 2 reachability

!
interface Tunnel1
description gre pri tunnel
bandwidth 1024
ip unnumbered Loopback0
ip hold-time eigrp 31 60
ip tcp adjust-mss 1300
delay 40000
keepalive 33 3
tunnel source FastEthernet0/1.1
tunnel destination z.g.h.3

interface FastEthernet0/1.1
description radio connection x.y.z.6 to isp
bandwidth 1024
ip address x.y.z.6 255.255.255.252
encapsulation dot1q 634

the other tunnel doesnt matter, my other link was working fine.

Why I posted this? Because I need some advice. The last version is the version I'm using now, but I would like a second opinion on the two versions I've posted. Or maybe some other solution. Thanks in advance.

This summer's (minor) network upgrade.

So, on Friday we started working on extending the data center. What we've done? Well, in order to accommodate the FPSO we really had to work a lot. Started at 20:00 on Friday and finished next day at 12:00. So about 16 hours. First thing done was cleaning the cabinets (ie throwing all the old cables and laying down new ones). Now what's so cool about this is that it will make life a hell lot easier since... well, i will later post a picture with the old cabinets so you'll get the big idea why now it's easier. Next, since the fiber leads were not in place yet (in the new trunking), we had to find some other leads and put them on top of the cabinets. Not a very elegant solution, but it worked. Next, since we Distribution and Access were collapsed into two Cisco 6509 switches doing HSRP. Since we had to accommodate lot of servers for the FPSO, we decided that the 6509s should be placed in the WAN part. So two stacks of 4x 3750 switches were set in place of this 6509s and .... well, to make a long story short , we switched from L2 to L3. Everything seems more organized right now, some parts have become more redundant (we had HSRP only on 6509 switches, now this moved to WAN part and everything became more redundant since everything has 2 or 3 fibers connecting here. Not to mention the new cabinets which each have 2 ups's , and since each router has two power supplies , each router is connected to two different upses. ) Tunnels are now terminating on a 3800 router (they were terminating into a 1800), and soon we'll change the raw internet router (now a 3620 which is barely over the minimum of what we need. not to say that with NBAR on place it used to choke before enabling NBAR on remote routers as well). Moved everything from Vlan1 to Vlan50 (at least for management purpose), made vlan400 for .187.0/24 class (Connecting the oil rigs ,remote locations and so on). Also Rami was kind enough to do some more overtime (I guess the guy spent about 24 hours here), and also upgraded the Call Manager so now it doesn't take like 15 seconds for each login/logoff.

The major network upgrade is not written (but took place). Kept me for almost 37 hours awake. Will post this at a later time.

idirect upgrade howto

I run into this a couple of days ago. I had to upgrade a idirect router (upload a new options file), but i did not had the password for iSite anymore. Here's how i did it:

1. Reload the idirect router.
2. Connect to the router with a cisco console cable
3. Login with username root and password iDirect (defaults)
4. ps ax ; and kill all the falcon processes.
5. # cd /etc/idirect/falcon/
# ls

falcon.opt falcon.opt.old

#
6. # mv falcon.opt falcon.opt.old
7. set your computer's ip address to be whatever the router connected to the idirect
modem/router was.
8. start a webserver on your computer
9. on falcon router : wget http://your-computers-ip-address/name-of-new-conf-file.opt
10.reload falcon router

that's it. Too simple, but worth writing for the future.

How about multiple internet connections?

Lets presume that one of your customers is buying two internet connections. One is from you, the other one is from the competition. Since he is not buying alot of bandwidth, he won't have much options regarding the usage of bgp, or some other routing protocol to switch between providers when one of his links is down. Here's a quick solution:

PS: this was a cisco 851

no service pad
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname example-customer
!
boot-start-marker
boot-end-marker
!
logging buffered 65535 debugging
!
aaa new-model
!
!
aaa authentication password-prompt password:
aaa authentication username-prompt Username:
aaa authentication login default local
aaa authorization exec default local
!
aaa session-id common
!
resource policy
!
clock timezone GMT+1 1
ip subnet-zero
no ip source-route
ip cef
!
!
no ip dhcp use vrf connected
!
ip dhcp pool example-customer
network 192.168.2.0 255.255.255.0
default-router 192.168.2.1
dns-server
domain-name example-customer.com
lease 2
!
!
ip tcp path-mtu-discovery
no ip bootp server
ip domain name example-customer.com
ip name-server
ip name-server
ip sla 1
icmp-echo source-ip
request-data-size 500
threshold 2000
tag providers-rtr
frequency 45
ip sla schedule 1 start-time now
ip sla 2
icmp-echo source-ip
request-data-size 500
threshold 3000
tag providers-rtr
frequency 45
ip sla schedule 2 start-time now
!
!
!
!
!
!
track 1 rtr 1
!
track 2 rtr 2
!
!
!
!
!
interface FastEthernet0
description Link to Provider1
switchport access vlan 2
spanning-tree portfast
!
interface FastEthernet1
description Link to Provider2
switchport access vlan 3
spanning-tree portfast
!
interface FastEthernet2
!
interface FastEthernet3
!
interface FastEthernet4
description Local LAN
ip address 192.168.2.1 255.255.255.0
ip nat inside
ip virtual-reassembly
duplex auto
speed auto
!
interface Vlan1
no ip address
!
interface Vlan2
description Link to Provider1
ip address 255.255.255.248
ip nat outside
ip virtual-reassembly
!
interface Vlan3
description Link to Provider2
ip address 255.255.255.248
ip nat outside
ip virtual-reassembly
!
ip classless
ip route 0.0.0.0 0.0.0.0 track 1
ip route 0.0.0.0 0.0.0.0 10 track 2
!
no ip http server
no ip http secure-server
ip nat pool provider1 prefix-length 29
ip nat pool provider2 prefix-length 29
ip nat inside source route-map nat-provider1-out pool provider1 overload
ip nat inside source route-map nat-provider2-out pool provider2 overload
!
access-list 10 permit 192.168.0.0 0.0.0.255
access-list 11 permit
access-list 12 permit
access-list 20 permit 192.168.2.0 0.0.0.255

no cdp run
!
route-map nat-provider1-out permit 10
match ip next-hop 12
!
route-map nat-provider2-out permit 10
match ip next-hop 11
!
!
control-plane
!
banner motd ^C
welcome dude.
^C
!
line con 0
exec-timeout 30 0
no modem enable
line aux 0
line vty 0 4
access-class 160 in
exec-timeout 30 0
transport input telnet ssh
transport output telnet ssh
!
scheduler max-task-time 5000
end

I took out some parts of the config and changed it a bit from what it looks like on the router, but it should work without problems.

Exim + DomainKeys Howto.

I ran into this problem a couple of months ago: all the mail one of my customers was sending ended up in bulk folder in Yahoo, Hotmail and other big free mail providers. While I was aware this will not solve the problem entirely, due to the fact that they open blindly any attachment in any email they receive (and thus get viruses which start sending emails/spam the next minute), I thought that I should also implement DomainKeys, since I was doing alot of maintenance work (like updating clamav, spamassasin and so on and so forth).

It took me a couple of days to finally get it working the right way due to different factors (dns, not being able to find a very comprehensive documentation, etc).

Here is what I came up with:

This is a quick tutorial on how to enable domainkeys (http://domainkeys.sourceforge.net/) on Exim on a FreeBSD server.

First, if you have not installed yet Exim, you have to install it. If you have installed it already, you have to recompile it.

The way to do it:

cd /usr/ports/mail/exim
ee Makefile    (or use joe / vi /whatever you like)

Search for the following lines:

# Enable DomainKeys support
#WITH_DOMAINKEYS=       yes

..and uncomment the "#WITH_DOMAINKEYS= yes".

Now you will have:

# Enable DomainKeys support
WITH_DOMAINKEYS=       yes

Save and exit the text editor.

Do the following:

make clean
make rmconfig
make
make FORCE_PKG_REGISTER=1 install  <-- if you already have exim installed. 
make install                       <-- if you don't have yet exim installed. 

Copy & paste in your console:

cd /usr/local/etc/exim
mkdir dk
cd dk
openssl genrsa -out rsa.private 768
openssl rsa -in rsa.private -out rsa.public -pubout -outform PEM
cat rsa.public

After all this you will have a result which will look something like that:

-----BEGIN PUBLIC KEY-----
MHwwDQYJKoZIhvcNAQEBBQADawAwaAJhAKJ2lzDLZ8XlVambQfMXn3LRGKOD5o6l
MIgulclWjZwP56LRqdg5ZX15bhc/GsvW8xW/R5Sh1NnkJNyL/cqY1a+GzzL47t7E
XzVc+nRLWT1kwTvFNGIoAUsFUq+J6+OprwIDAQAB
-----END PUBLIC KEY-----

Save whats between ---BEGIN PUBLIC KEY--- and ---END PUBLIC KEY--- for later use.

Edit with your favorite text editor /usr/local/etc/exim/configure

find the line which starts with "remote_smtp:" . This should be under the "begin transports" section of the file.

It looks like that:

remote_smtp:
  driver = smtp

Edit there and make it look like that:

remote_smtp:
  driver = smtp
  dk_selector = myselector    # you will need this later when you will alter your dns config
  dk_private_key = /usr/local/etc/exim/dk/rsa.private
  dk_canon = nofws

Save the file, exit and start/restart exim :

sh /usr/local/etc/rc.d/exim.sh restart

Login to the server that serves as DNS server for the domain name for which you are configuring this domainkey thing.

Go to /etc/namedb/

Find the file corresponding to your domain (look for it in named.conf and you will find the path to it).

Let's presume is /etc/namedb/pri/com/yourdomain.com. Edit this file, and just after/below the IN MX statement, add the following things:

_domainkey.yourdomain.com.       IN      TXT     "t=y; o=-"

myselector._domainkey.yourdomain.com.  IN      TXT     "k=rsa; t=y; p=MHwwDQYJKoZIhvcNAQEBBQADawAwaAJhAKJ2lzDLZ8XlVambQfMXn3LRGKOD5o6lMIgulclWjZwP56LRqdg5ZX15bhc/GsvW8xW/R5Sh1NnkJNyL/cqY1a+GzzL47t7EXzVc+nRLWT1kwTvFNGIoAUsFUq+J6+OprwIDAQAB"

Alter the serial (for example, if today is 28-aug-2007, make your serial look like 2007082800 or 2007082801, etc), save the file and reload named.

if your domain is something like customer.yourdomain.com, then the records will look like that:

_domainkey.customer.yourdomain.com.       IN      TXT     "t=y; o=-"

myselector._domainkey.customer.yourdomain.com.  IN      TXT     "k=rsa; t=y; p=MHwwDQYJKoZIhvcNAQEBBQADawAwaAJhAKJ2lzDLZ8XlVambQfMXn3LRGKOD5o6lMIgulclWjZwP56LRqdg5ZX15bhc/GsvW8xW/R5Sh1NnkJNyL/cqY1a+GzzL47t7EXzVc+nRLWT1kwTvFNGIoAUsFUq+J6+OprwIDAQAB"

Remember to also modify /etc/namedb/named.conf:

Add the following to your options { ... } section of named.conf

        check-names master ignore;

This will allow you to use _ (underscore).

You will have to edit and add that "check-names master ignore;" thing if you get the following error in your logs:

Aug 28 15:02:33 noc1 named[83277]: pri/com/yourdomain.com:15: myselector._domainkey.yourdomain.com: bad owner name (check-names)
Aug 28 15:02:33 noc1 named[83277]: zone yourdomain.com/IN: loading master file pri/com/yourdomain.com: bad owner name (check-names)

The long string after ....."k=rsa; t=y; p= is your public key which i said you should keep for later use.

To test send an e-mail to dk at dk.crynwr.com . You will receive about 5 messages back from different addresses with test results.

If any of them says test passed you should be ok. Send an e-mail to a yahoo.com e-mail address and check the headers.They should look like this:

From Dan Caescu Tue Aug 28 06:20:08 2007
Return-Path: 
Authentication-Results: mta233.mail.mud.yahoo.com  from=yourdomain.com; domainkeys=pass (ok)
Received: from x.x.x.x  (EHLO relay.yourdomain.com) (x.x.x.y)
  by mta233.mail.mud.yahoo.com with SMTP; Tue, 28 Aug 2007 08:16:56 -0700
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=myselector; d=yourdomain.com;

That should be all.

Good luck!

PS: I also posted this here: http://wiki.exim.org/DomainKeys You will also find there some other useful documentation.