Cisco :: Distinguishing Whether RST Packet Is From Closed Port Or Not
Feb 23, 2011
I have two servers: serverA and serverB. In serverA there is a ssh session open to router1 from source TCP port 41760(from ephemeral port range). Is it somehow possible to detect from serverB, is there is a process associated with TCP port 41760 in serverA? I mean if I check with nmap, I receive a packet with RST flag on, but I'll receive similar packets for closed ports as well. Is it possible to distinguish, whether a RST packet is from closed port of from port, which has a session established with another host?
I have followed all instructions to forward port 22 on my netgear router WNDR 3400v2. It says it forwarded but according to port tracker. Its closed. I am having this with two different locations. All IP addresses are correct and the router can ping them. It just wont open. Using SSH program for port 22 access.
I have a Netgear wnr2000v3 Router connected to my Motorola Surfboard Gateway.I have a freePBX Server (virtual running off of VMware Workstation 8) that needs ports 10001-20000 and 5060 forwarded to the server at 192.168.1.110
I added the portforwarding as in this photo:
When I use a port tester it still says "Port 5060 is closed"I have also turned off Windows Firewall. What else could be blocking these ports?
I have a Cisco ASA 5505 with a fairly simple set up. Few VPN tunnels and only 3 open ports for applications. I have entered the following lines static (inside,outside) tcp interface 9002 10.0.3.230 9002 netmask 255.255.255.255 access-list outside_access_in extended permit tcp any interface outside eq 9002.I have done this before with zero issues. The other two ports are open, however, port 9002 will not be visable from the outside. The ASA says it is open, but if I go to a site like canyouseeme, it shows closed. I cannot connect to the application either.
i have a 54G wireless home router ..... successfully port fowarded an application from a CPU (server).... but after no connection made from the user to the server..... it suddenly close the application ..... so what i did is to reboot the router in order to refresh the connection ...... Is there any other ways to fix this sudden close of the ports ?
I have always done my port monitoring (SPAN) on Cisco layer 3 switches with no issues. This time I am trying to do this on a Cisco 2901 router:
Cisco IOS Software, C2900 Software (C2900-UNIVERSALK9-M), Version 15.1(4)M2, RELEASE SOFTWARE (fc1) System image file is "flash0:c2900-universalk9-mz.SPA.151-4.M2.bin
I need to have the source port gig0/0 and destination port gig0/1. There is something about the gig port enumeration (slot/port#) that makes the command rejected. It is self explanatory:
#sh ip int brie Interface IP-Address OK? Method Status Protocol Embedded-Service-Engine0/0 unassigned YES NVRAM administratively down down GigabitEthernet0/0 xxx.xxx.xxx.xxx YES NVRAM up up GigabitEthernet0/1 unassigned YES NVRAM up up Serial0/0/0:0 unassigned YES unset up up
It doesn't matter what slot or port number I use, it is always rejected. The command is rejected for Both destination and source gig interfaces. I tried a wide variety of slot/port numbers. To my best understanding the complete port names are: GigabitEthernet0/0 and GigabitEthernet0/1, so why does it think there has to be another digit after 0/0 or 0/1? Does it have anything to do with the Embedded-Service-Engine0/0 being administratively down?
We have the port on the switch set like this: switchport port-security maximum 25 switchport port-security switchport port-security aging time 2 switchport port-security violation restrict switchport port-security aging type inactivity
In case a device connected to the port is inactive for more than 2 minues ( aging time ) the first frame/packet the device generates arrives to the port on the switch, but the switch does not forward it to the appropriate port ( discards it or whatever ).
So far I tested on 1 30 WS-C3750E-24PD 15.0(2)SE2 C3750E-IPBASEK9-M 2 30 WS-C3750E-24PD 15.0(2)SE2 C3750E-IPBASEK9-M 3 52 WS-C3750G-48PS 15.0(2)SE2 C3750-IPBASEK9-M
When we remove port security from the port, it works perfectly fine, as expected.
It seems this is not HW or IOS version related. It seems it is not a stack synchronization issue, it does not matter if a device is connected to the first or other stack member. I tested on C3560 too, here there are no problems, so seems it is 3750 related.
i still newbie to configure eBGP, i have Router 3600 series, and i configure BGP neighbor to my ISP, but the peer still don't established,there is warning like this, Connections established 339; dropped 339 "Last reset 2w4d, due to Peer closed the session No active TCP connection"
any one can explain to me about "due to Peer closed the session"? i've read some documents for troubleshooting BGP, and do some step to troubleshoot.
Can open (url) in work computer but not at home - Message coming up at home that it will be closed for maintenance and that was last week and has since finished now as i can open site at work but not at home
I have my 2Wire AT&T U-Verse router properly set up to forward the port 25565 from my machine. (Incidentally, PortForward.com gives me a blank page when I try to look up how to do this.) However, when I test the port is indeed open ( Open Port Check Tool - Test Port Forwarding on Your Router ), it returns as closed. Yes, I'm running the server software while I run the test. I only have the Windows Firewall, but I ran attempts while the firewall was completely disabled as well as with just the appropriate programs allowed.
I have a problem trying to forward ports needed for steam: my connection to internet looks like this Cisco epc3212 cable modem -> netgear wnr3500v2 ->my pc, all via ethernet cable I set up static ip for my pc and forwarded ports in router but after checking results on web port scanners it only changed from timed out to closed. I have no firewalls, neither on my pc or router, i called my isp and they told me they don't block any ports. I have windows 7. After trying dmz all my ports remain closed except for 3389 which is remote access for windows. I.ve been working on this for past few hours and i'm loosing my mind .
We operate a home office network (workgroup) of 6 older PCs running Windows XP SP3.It's a Windows based network using a designated "home" PC as a server, and until recently we were using ethernet cables and a hub/switch for sharing files which worked well because we only share small document files, no music or video.The workgroup does not have a shared internet connection, we don't want or need one for what we do, although the individual PC's can connect to the web using USB dongles just for checking e-mail.Recently the ethernet hub died and I decided to take the opportunity to upgrade to wireless file sharing.None of the PCs have inbuilt wireless adapters so I bought a D-Link USB wireless adapter for each PC.I also bought a Netgear N300 router, thinking that this was suitable entry level equipment for wireless file sharing. Now I'm not so sure.So far I was unable to install the router on the "home" PC because the installation CD seems to assume that the router will be used for sharing an internet connection and does not seem to offer an installation option without a standalone modem. How to install this type of router to create a closed home wireless network without a shared internet connection.
I have a Dell Studio 1537 running on Windows Vista? my computer stopped being able to connect to the internet a few days ago and a "Dell Wireless WLAN Controller closed and stopped working" (or something along those lines) box would keep on popping up. I did some reading around on the internet and decided that maybe I needed to update the "drivers" for it so I went to the Dell website and downloaded the most recent version for my Dell Wireless 1510 WLAN mini card...that didn't seem to work any after I installed it. So I went ahead and uninstalled it (I assume I must have uninstalled something I shouldn't have) and now I'm stuck at the same problem. I can't connect to the internet!In Network Connections, it continually says that "Windows cannot find any networks". In Device Manager, under Network Adapters, it doesn't list the card there, although it lists "Broadcom Netlink (TM) Gigabit Ethernet". And from some suggestions I found on the net, I tried ipconfig/all in the comand promt and it says "media disconnected".
I have disabled windows firewall in Windows 2003 server control panel but only few ports are shown opened when i scanned with advanced port scanner why other ports are closed.How to open the closed ports?
I was trying few days ago a tutorial of SSH tunneling, but I got an error,"server unexpectedly closed network connection", although I did everything like in the video tutorial and port 433 was not closed.
We have a WRT610N and are having trouble getting access out to the internet with an FTP client.We are trying to configure Sync2 a program from 4team.biz. It is an MS Outlook application that utilizes FTP servers to host .PST files (outlook data bases) for synchronization.The software has an FTP client built in that can access FTP accounts to store and synchronize the .PST file.
The issue is the WRT610N will not allow this client to connect to our FTP account. We had 4Team’s tech support working on it for a few hours. Ultimately they decided it was my router causing the problem. To demonstrate this to us, they tested ports 80, 21, & 22 utilizing the following websites: url...
All the ports showed either closed or not responding.How do I open these ports so that I can allow Sync2 to communicate with the our FTP account? We are hosting out FTP site at 1and1.com.
Issue: Whenever I close my lid, my wireless connectivity drops by around 80+%. When using speedtest.net, I normarlly download at 5 megabits/s and upload at 1, but with my lid closed, I download at less then 0.4 and upload surprisingly at 0.8. My downloads and torrents basically grind to a halt, multiplayer gaming becomes difficult and websites/youtube/videos take much longer to load. I can check all these figures as I'm using an external monitor.I have tried a lot of things to improve connectivity including setting everything to high performance, disabling power saving modes, setting roaming to aggressive/high and updating drivers.
I was upgrading the firmware of the WRT54G router when the notebook´ screen closed and it went to standby mode. It was stoped the upgrade process.Now only the ports and Internet LEDs light up, but the power LED is off.I also cannot connect to thenavigator for show the administrator´s window. Any procedure to recover the operation of the router in a situation like this?
I regularly get this message (but not everytime) when I start up Windows Vista Home Premium 32-bit.
"Dell Wireless WLAN Card Wireless Network Controller stopped working and was closed.a problem caused the application to stop working correctly. Windows will notify you if a solution is available."
Then I get this following message:"Solution Found: Address a problem with your WLAN card.Your WLAN card has stopped working properly. This is a network adapter that allows your computer to connect to a wireless network. To find out if an updated version of your WLAN card is available, contact your device or computer manufacturer."The strange thing is even though I get this message I am still able to connect to the internet via a wireless network. So there is no problem as such it is just annoying to keep getting this message when Windows starts up.I have checked on the DELL Support website and I do have the most up-to-date driver already (Or I think I do).
My workplace has a UC-540 attached to a cable modem, attached to the world wide web.
When we make VOIP outbound calls through the standard ISP, there is no auditory packet loss sympton; however, when we make calls to out sister branch through our VPN, we experience auditory packet loss symptoms.
I would think the VPN should only be affecting the encapsulation of the data. To my understanding the VPN packets and non-vpn packets all hit the router at the same time, and transport over the web in the same manner. Why would there be packet loss over only the VPN??
--Regarding QoS, if a standard layer 3 device receives a VOIP packet encapsulated in a VPN, do the QoS bits in the VOIP packet get acknowledged, or are they hidden by the VPN encapsulation?
having some issues. My basic VOIP network I can get to work no problem uner Vlan 1. But when I try tomake multiple basic networks to connect and put them in to diffrent Vlans such as Vlan 2, 3, 4 and conect them the phones now say configuering IP.
Isn't there a way to increase the TTL of an OSPF Hello packet or am I thinking of a different protocol? Or is it only with virtual links? I can't seem to find it in my ROUTE cert book or on the Intarwebz outside of setting TTL security, but I could have sworn I remembered configuring something like this in my ROUTE lab book that I unfortunately do not have at work.
I having a basic query in troubleshooting E1 link , here im facing packet drop in the link and we are testing by providing local loop and remote loop from the CSU/DSU at local point and at remote point . I have tried ping test while the loop is given at local point and remote point ie i have pinged my local serial interface IP address (eg 10.0.0.1 -local & 10.0.0.2 -remote ) in Remote Loop i could see no errors and drops and also the traffic on the interface output and input is the same(eg input rate 1000bps and output rate 1000bps) .My query is that when i am pinging the local interface IP does the icmp packet travels till the loop point and comes to the same interface(like a boomerang) .
ICMP packet ->->->->->->->->->->->->->->-> R1 Local CSU/DSU | Remote CSU/DSU (remote loop given )
We are working on taking a port off of a switch and connecting it to a mux (TAC 900). Port is trunked to another switch in another geographic location. From wht I am being told from the engineer who handles the transmission end of things he said once our segment is physically connected the mux will crash. He supplied the error code to the vendor and they said it is crashing because of a jumbo packet in excess of 1536 bytes. Soon it will be a moot point as the hardware will be, upgraded but we need tis running NOW.
im in the progress of Configuring a Cisco 881 Router, for a branch office.Behind this Router they have an PBX, is it prossible to inspect SIP packet using CBAC, and thereby open for RSTP pinholes.i only have 1 Public ip adresser, and im not fond of configuring thousands of PAT to the PBX.i have with success, Accomplished this with Global Inspection on ASA Firewalls, but i dont know if this can be done with IOS as well.