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Information about alg.exe file

File: alg.exe
Name: Application Layer Gateway Service
Product: Windows
Manufacturer: Microsoft
Risk factor (Virus/Trojan/Spyware): Rating

Application Layer Gateway service is a component of of Windows OS. It is required if you use a 3rd party firewall or Internet Connection Sharing (ICS) to connect to the internet. Do not end this program in task manager - you will lose all internet connectivity until next restart or login.

Note: The alg.exe file should appear only the C:\Windows\System32\ folder. If you happen to find this file in a different folder, it is possible that your rundll32.exe is in reality a malicious file. Many trojans and viruses try to cloak their real identity by using the names of legitimate files. Any time that you encounter a suspicious process, you should verify the digital signature and the file path, for example using Anti-Spy.Info.

User feedback

There were 1381 user requests for that file. 75 users classify it as harmless. 10 users classify it as not so dangerous. 42 users classify it as neutral. 20 users considered the file to be suspicious. 23 users classify it as bad and recommend to delete alg.exe. 18 users didn't classify it ("don't know").

RatingApplication Layer Gateway Service Alex
Ratingfile is located in the c:\windows\System32 folder nithin
RatingIts an important program but can be linked with parasites God
Ratingwhen this application is active this cause to accure error while i want to close windows explorer or internet explorer.after terminating this task everything is ok. nice fox
Ratingit's a microsoft based file. Emrah
RatingDescription: Part of Internet Connection Sharing application and Internet Connection Firewall for Windows XP. This service provides support for third party protocol plug-ins for the Internet Connection Sharing application and Internet Connection Firewall.  link for more info gkalia
RatingKnocked the damn thing off with aports.exe, don't see any problem, everything works fine Lysander
RatingICS file no need to worry eddie
Ratingit may legitimately be found in other folders on XP systems Dorkster
RatingALG.exe means Application Layer Gateway Service. It's used for internet connection sharing. Stay cool. Mariano
RatingKnown Spyware/Trojan. IT is known for its unique ability to reconfig your regestry...HS.Hack.34 McAfee Virus Tech
RatingIt is used by windows XP firewall... To prove it, go into your network properties and turn off your firewall. It will disapear from your task list. So if you want your firewall to work you had better leave it! (Dont forget to turn your firewall back on!) Shane
RatingIt's Microsoft specific, required for XP SP2. NOT DANGEROUS. Not SpyWare/Trojan as some have said.
Ratingyou can disable it, but you will lose MS firewall (not big deal), Internet connection sharin. if u dont need it, disable it and save resources marcofulvio
RatingThis item shows up in your process list in Windows XP if you turn on the personal firewall built into XP. You can look for firewall in windows help to learn how to turn it on and off. DarkRider
RatingNormally fine, but something changed mine to stop Norton from autoscan & email scanning capabilities. Chris
Ratingsince I applied microsoft firewall on my computer, als.exe is appear on backgound process. don't worry ,it's not harm dadan_konsol
Ratingit's knocking off my explorer when i try to get this file's properties and i don't know why, that's why is suspect
RatingLag direkt unter D:\ Hans
Ratingthis archive bring me problems to play multimedia KLEYDO
Ratingxp firewall is disabled and yet it still appeared.
RatingUseless crap from M$ that gets started even though you don't need or want it Bob Gates
RatingHabe Datei entfernt Internet geht aber trotzdem noch Steffen Brosche
RatingTill now I used to believe that it's creating trouble with the internet connection or something. So i always turn it off from the task manager. But now i learn that it;s a windows internal process. not sure really. could it be possible that alg.exe gets infexted with viruses easily. Or is it possible that alg.exe lets access to my PC or else lets some malicious program communicate with its server when i am connected to the internet. ddas
Ratingalg.exe is located in "C:\WINNT\SYSTEM32\" on Windows 2000 and "C:\WINDOWS\SYSTEM32\" on Windows XP. If the file alg.exe is in other place, it could be a spyware, trojan, worm or virus! zero
RatingYou can disable it if you have 3rd party Firewall. james
RatingThe service is NOT dangerous; if you use other firewall than MS and you don't share printers, files or computer resources in a network you can disable the alg.exe service; however, if you do share your PC resources, leave this service alone cause you'll need it.e Parsifal
Ratingwhen i setup my windows xp professional if any problem comes to me then i press ctrl+ alt+ del just iget taskmanger how can i found it which is the important file of operating system and then i press endtask
RatingIt appeared after WinXP SP2 was installed and their Firewall enabled. It stayed around after I stopped the firewall, and so I hit "End Process" in the task manager. No problems. Andrew
RatingKilling ALG.exe on WinXP SP2 doesn't stop internet working at all on my box. Agree is used by win f'wall. Adrian
Ratingapparently alg.exe craps up several useful little tools like internet explorer. i'm having to kill it regularly to keep IE from crashing on me. Gralgrathor
RatingCame up immediately after installing XP SP2 - Seems to be for the XP firewall as others have reported lasher62
RatingDisable the xp firewall (if you don't need it) and it disappears. *shrug* Kachiko
RatingPops up even if you disable XP Firewall !!! Rename it and it'll never come back (like msmsgr.exe)  link for more info OtherFox
Ratingwhat i know is i have it no harm gus..don't worry Aiman_AZmi
RatingI know that Shane is WRONG...I disabled the firewall,'s still there joe blow
Ratingappeared after run xp sp2 so I assume firewall process is the story behind it! mtis2000
Ratingis more dangerous, it a trojan Netanyahu
RatingIt is simply explain in Services. Go to Control Panel, double click Administrative Tools, double click Services. it's next to Alerter. omega13
RatingWhenever windows XP starts up this alg.exe LOCAL_HOST, I can no longer access the internet and need to reboot. Very irritating. CS
Ratinglocated in c:\windows\system32; c:\windows\prefetch; c:\windows\servicepackfiles\i386; c:\windows\softwaredistribution\download\75e4029c35a8b37105984119f6cd14 all files sized 44kB.. internet works totally fine when alg.exe running.. lacks the guts to delete/end task Canute
RatingI know after installing servicepack Xp om my 600mhz ( with 500mb ram ) my computer got slower. i dont need it when i have tcp and udp control in my router.. T
RatingDefinatly used as a server by psrticulsr trojans and worms to relay back to other computers. \trust me, I just spent 3 hours cleaning it all up. It is a legt file but can be manipulated (e.g. svchost.exe) Chris
RatingDisabling the XP firewall doesn't always remove it. It certainly causes problems with explorer and my PC "freezes" for no reason on occasion when it is active. Bredwell
RatingALG is a service which can be disabled in the Services MMC. It WILL NOT disrupt your internet connection. I am a Networking professional, Certified! Doc
RatingWhen I start up my computer, this alg.exe starts. When it's running, I can't connect to the internet. When I kill the process, internet works fine. WhI$tTL£R
RatingWenn sich die Datei nicht im System32 Ordner befindet, dann ist es ein Virus oder ein Trojaner, sonst ist es harmlos raptor99
RatingIt appears as part of the Firewall in SP2. It's a service and can be disabled once you disable the Windows Firewall. SD
RatingIt is part os XPsp2. To make it go away turn off "Windows Firewall/Internet Connection Sharing (ICS)" BOFH
Ratingits an official MS file. you can look it up on their site, they have a process info page. freaky
RatingThis is not a virus, It is a file with SP2 for the new firewall, and security centre. Kevin H.
RatingNeutral, Part of windows firewall, doesn't consume that much memory. Sérgio Santos
Ratingzonealarm want't to block it, did it and everthing works fine :) el_Loco
Ratingisn't bad at all...just with the new windows firewall. jen
RatingSi se borra no pasa nada con las conexiones de internet ilich
RatingIt is possibly a worm.  link for more info Ben Dover
Ratingsiksok bisey iste alomelo
Rating  link for more info kaleos
Ratingaccording to Symantec, may be part of the W32.Petch virus, which is extremely dangerous.  link for more info Frank Ross
RatingCame with XP SP2 and claims to be needed for 3rd party firewall operation as well as IC sharing. Apparently before sp2 my IC and firewall were working fine without alg.exe service listening on the background. Renokan
Ratingit loads with outpost, as it was told on this site  link for more info NickiSpeaki
RatingHas to do with the Internet Connection Firewall, but about 5 minutes after I enabled the firewall, Norton told me I had a worm on my computer. Gary
Ratingi got infected with this alg.exe by visiting a website. it disabled my virus scan's internet filter. very tricky. Someone help me! i just rebiult my computer yesterday Evan
Ratingtried to contact It is located in c:\windows\system32...seems to be a trojan newHere
RatingWindows file!! like any other windows file, not dangerous in case you keep your windows updated. Mohamed Elnamaky
RatingThe file *can* be a trojan but often isn't. You don't just disable the firewall to get rid of it. You have to stop the process from starting at startup, try the registry or msconfig program. It is *not* always a trojan and it is not useless M$ crap. If you don't like MS run linux. Better than "McAffee spyware tech" fool
Ratingalg.exe keeps port 1033 open (Netspy trojan port). Netspy is a relatively rare, however extremely powerful trojan. AOL tech (fun stuff)
Ratingit starts even if windows firwall is diabled. Go to Control Panel, double click Administrative Tools, double click Services. disable and stop. fugedabowdit
RatingMy explorer crashes while alg.exe is running. Disabeling it like omega13 described solved my problem, and freed 600k of memory. WOHOO! Gyner
RatingJust freaking go to run and type services.msc Now go to the Application Layer Gateway Servie properties. Now stop it and then select "Disabled" for startup type. Now it's gone and will never run again. Renaming files is not EVER the best solution, errors could occur if the file is not found. Diable it the correct way. Hank Hill
RatingI read that if you disabled the firewall, and had ICS off, that ALG would not run. Well, both are disabled and it's still running. I'm suspecting it to be the source for some of my connection problems elsewhere... Johnboy722
RatingI found alg.exe in three different folders. I disabled them all, but the file in the System 32 folder and I regained control of my Internet Explorer. I am not sure it is completely legit. Looks like it depends on its location. ELEGANCE
Ratingi tried to delete a folder, but i wasn't able to do this until i terminated this task. juna
RatingIf you don't share anything or use MS firewall, get rid of it. John
RatingDUH!!! Trun off your firewall and see what happens. This is an ICS related program and is Neccasary if you want to use windows firewall. Rebber
RatingProvides support for 3rd party protocol plug-ins for Internet Connection Sharing and the Windows Firewall. Absolute
RatingThis file is also under SP1 But it's unstable on SP1(a) XP comps. Use alg on SP2 only. Sn0WDr4gon
RatingApplication Layer Gateway service is a component of Windows OS Someone
Ratingthe original purpose is 1 of 2 things.... windows run firewall, or ICS (internet connection sharing).. so you can disable the whole service package under controlpanel/admistrative tools/services"windowsfirewall/ICS" if you have your own firewall and an external router. if you are using windows firewall or are using the machin as an internet gateway for other machines, then leave it on. it is possible it could become corrupted, never seen it in the wild though Delta-9
RatingBen Dover is wrong. On his link it is said that some internet worm DELETES alg.exe. This surely does not mean that alg is a worm. Of course it is possible that a parasite can have any name, including alg.exe, but Ben's link shows no evidence of that. marginal
RatingIf you have a firewall you can turn ALG off in the "services.msc" in the run command. Though only turn off stuff that you know you don't need. Turn the wrong stuff off and you'll have to reinstall OS from scratch. leviathan
Ratingdisabled by zone alarm,noticed nothing wrong fonito
RatingIch finde die alg.exe mittlerweile auch ein wenig suspekt... da er Port 21 benutzt und sich grundsätzlich mit anderen Usern verbindet (whois abfrage), denke ich die alg.exe wird wohl dazu benutzt werden um von einem remote rechner Zugriff auf den eigenen Rechner zu erhalten.
Ratingit's in 3 different locations "C:\windows\$ntservicepackuninstall$" "C:\windows\system32" "C:\windows\servicepackfiles\i386" also the one under uninstall folder is smaller in size bean
RatingOh, that was WinXP home btw...and you can just goto control panel--open admin tools--services--and stop the program/restart the program bean
Ratingi have SP2 and this file is both in c:\windows\system32 and C:\windows\ServicePackFiles\i386 .is there any threat of virus here? thanks Arian
Ratingyeah its microsoft maybe but tends to lock the workstation, when i kill it all seems to revive so if you have other firewall local or on your LAN kill it 4 goot and you will not regret :) Jur
Ratingi dont kwno why everyoen says sp2 i dont have sp2 and its on my system, could be cause i have aol put on and i dont think i noticed it before gerald
RatingFOR BRAZILIANS: não sei o que ele é realmente. Mas acaba trazendo alguns erros, por exemplo em jogos que ocupam memória 3D ele os diexa mais lentos INTERNET SECURITY CENTER BRAZIL
RatingA firewall integrated in XP Roberto
Ratingit sux... it slows my internet down.. f**king M$...
RatingThis file is also in SP1 machines. It is not specific to SP2. I use ICS so I have the file running. No problems here at all. TuT
RatingSeems like there is some Spy-ware with this name too! 2 are legit (c:/windows/system32 and in the updates folder, both dated 08/2004 and 44KB. The mean one 's got 16KB and is in a different folder. Deleted it, restarted, and everything worked fine again with the genuine ones. Georg
Ratingseems to be associated with spyware on my pc. The time I see it running when I'm getting pop ups and such.
RatingI'm on a LAN running DSL. I end the process while downloading a file from the internet, nothing happened. I do know it popped up after installing dangerous Active X controls which did have a crap load of spyware and junk in it. So take it how you want it. aR6guy
RatingIf u pc share internet connection, windows xp need this aplication to run, now in my language ;) Si tu pc comparte conexion a internet necesita tener cargado ALG.EXE
RatingKnocked down my IC, I could ping ip-s in the outside, but win wasn't able to get the ip-s for the www adresses from the dns server. I killed the process, everything works fine. mutra
RatingIt is necessary.Do NOT end it.. Turker
RatingIts common if you run McAfee firewall Noreaga
RatingMicrosoft application  link for more info Benji
Ratingi know as a good senior computer user that it is a trojan !! please read everything on the link and it will prove that it is what it is.the creators webside of the trojan is offline so in fact its no longer harmfull ((i think)) its easy to delete just click on search file. its not from microsoft system or any updates!!!  link for more info Alex Raptor
RatingThis is just the Windows Firewall/Internet Connection Sharing (ICS).  link for more info zionid
RatingIts not a dangerous file, but uses resources anyway. It exists also in compressed Service pack files and uninstall folder of service pack. If you see it in a weird folder, it might be suspicious. If you dont use Windows Firewall and if you dont share your internet connection, you can disable it. It can be disabled and stopped from local Services (Administrative Tools) -or as it explained here many times- by Start (button) Run (typing) services.msc . It is the 2nd service from the top (after Alerter). Double click on it, "Stop" the service, and change the "Startup Type" to "Disabled". Click ok. ilteractive
RatingAnche se ho disabilitato il FIREWALL di WINDOWS (ho un altro firewall) lui entra sempre ed e' allocato sul file di sistema (C:\windows\system32.....)...non crea alcun problema anche se i dubbi restano..... AlexFmItaly
Ratingit floods the ram when using file sharing program ie DC++ Odd Hermit
RatingThis file suck. After I connect trough Dial-Up to Internet all connectivity stops after 5 minutes. If I shut down from Taskmngr alg.exe everything is OK. Fade2black
RatingKönnte auch noch in dem Ordner /i386 des SP vorhanden sein! Alfthe1st
Ratingsome time this alg.exe hanging up my internet connection i i need to kill this task in order to have inet connectivity Valentas
RatingWenn man sie "friedlich" beendet, wird die Internetverbindung auch nicht gekappt: Unter Systemsteuerung - Dienste ganz einfach "Windows-Firewall/Gemeinsame Nutzung der Internetverbindung" beenden und dann vielleicht noch den Starttyp auf "Manuell" oder "Deaktivert" setzen. UnRobbar
Ratingalg.exe is a 40Kb file - a potential windows exploit. It opens a port allowing your system to be vulnerable with potential of full exploitation. Sp1or2 has this window component. ICF/ICS allowing Windows firewall and third party plug ins and perhaps alteration to the firewall. Disabled, I find no current issues. It may be re-enabled via the internet if your system is vulnerable. Very Wairy!!! Mr. TC
Ratingsame as listed originally, If your behind a firewall router, you dont need this exe taking up cpu cycles. John
RatingHad an outside port connection to it, no alg.exe file was found on my hdd. It was killed through task manager. I recently started windows firewall but there's NO reason it should have a live connection like that. Very bad.
Ratingsystem process jj
RatingMy connection was boosted 50% after i terminated this one. Boris
RatingApplication Layer Gateway Service (Alg.exe) Windows Firewall/Internet Connection Sharing (ICS) component  link for more info crae
RatingIf you don't need the firewall and ics, you can disable the service "Windows-Firewall/Gemeinsame Nutzung der Internetverbindung" and it disappears. Joe
RatingI think its somehow linked to spyware or a virus. Since i installed Divxtrailbundle, which is ment to have the gain spyware, the Alg.exe is trying to connect to the net ( according to norton firewall -in pro-config-). But you will never see it connect unless you turn all blocking options on ( external moduls check.....and programm launch monitoring ) I never used the windows firewall. JUDAS
Ratingfresh install with sp2 slipstreamed, after a hour online sygate came up asking if i wanted to let alg.exe ftp out to such-and-such address and thats with xp firewall off and no ics on this puter, did a search and found it only in the /system32 folder, you tell me, if it was a needed program why is it trying to ftp out to a non microsoft ip? for that matter why is it trying to ftp out at all?
RatingMalware authors have used this exe name. Tracking back from firewall logs led me to three owned laptops with non-system32 directories alg.exe's running as the top process while tcpdump showed the laptops busily trying to audit netbios shares....don't nuke out of hand..there is a real alg.exe...but don't assume that it's presence in a ill machine's process stack is 'good'. My advice...if you see it as your top process start tcpdumping the traffic from that machine, even if it's the legit alg.exe, at best something is pestering that station's firewall Another BOFH
RatingWhat i know is that most of you seem to thrive on gossip. maintain good antivirus ( this means updating more then once a year :) ) use a good malware detector periodically ( i wont mention names as that seems to open can of worms here and Above all use common sense. You only get infected if you are lax in prevention. in conclusion ANY file could in theory be harmful as you can rename them anythign you want windows doesnt really care. Most infections i encounter are due to lack of knowledge on machine owners part and by uninformed people who want to download "HACKS" of various types peace Wildman
Ratingcan't go to any sites or use internet, i killed and things start working again beef stu
RatingWindows System Process for Internet Connection Sharing  link for more info Nathalie Oldenburg
Ratingwell it blocks all connections to internet that what i m experiencing suleyman
Ratingjust when the windows start it is executing as i see in the task manager and my floppy drive and cd drive as getting accessed unnecessarily and when i end the process they DONT...... shakeel
RatingThere is a worm connected to this that is a file called W32.Petch. If executed it can change your registry & delete system files. I did a search on alg.exe, found your site here, then went to Symantec and read about it & am trying to do a scan to find it. It must be what's screwed up my antivirus that isn't working this a.m. Jackie
RatingIt can be configured in firewalls not to access internet and still work. I have it blocked full time and i can still dial up and connect etc. Troy or Eva
RatingSpyProgie von microsoft - sicherheitskopie machen und dann löschen, wenn der PC rund läuft, ok - wenn nicht die datei wieder herstellen. Aber -- never change a running system - *zwinker PC-Guru
RatingIt is a normal process, not harmful. Should your Firewall detect access to this file, block it, and you won't have any troubles with it. Dan
RatingIt appears to bring stability back into my system by disabling/stopping it. Of course, we do have other firewall protections... however of note, the false statements listed above COULD have been by those that enjoy exploiting it's weaknesses. Not to mention find people that only lightly understand this arena; therefore, I suggest maximum caution when giving away personal information..such as your email addy which could contain your DOMAIN......might as well advertise that you don't lock your house and oh, btw, take down my address, stranger. PredatorHunter
Ratingwhy does it want to connect to port 4777 John Purdue
RatingDie alg.exe ( Application Layer Gateway Service) stammt von Microsoft. Sie wirkt mit, wenn mehrere Computer eine einzelne Internetverbindung nutzen. Zum Anderen ist Sie Teil der Internetverbindungsfirewall (ICF). DataFighter
RatingWindows still launches alg.exe even if 3rd party firewall is being used. Suggest disable alg.exe in services (See Hank Hill Post Above) When running alg.exe system can be compromised real-time all the way down to CMOS racerdog
RatingThis file only apears in TaskManager for me when sharing my internet conection. If you have any doubts, and are not using a firewall or sharing a conection, I would look into turning off *Remote desktop, *Error reporting, and *File sharing of ANY kind. Hold windows key and tap Pause/Break button for System Properties to appear. ETC. 1541 SID
RatingI found this process running and using a program what's running. It located it with an open port 1029, under ip connections and the name of a computer attached to my workgroup running this file was called, not part of my workgroup, seem like a Trojan to me. I ended the process no problems with internet connection.  link for more info Tomg802
RatingThe darn wast of RAM isn;t needed for 3rd party firewalls. I use Zone Alarm, and don't run the program. RLS0812
RatingBefore the installation of Service Pack 2, this service was required for use with the Windows Firewall/Internet Connection Sharing * service. After the installation of Service Pack 2, it no longer is required. No Dependencies. RCAdmin
RatingMy PC just freezes, monitor goes black and I have to restart. Without this thing running, everything is fine. Maybe it is not compatible with some other applications running in the background. Seppel
RatingHabe die Anwendung unter Verwaltung- Dienste als "Gatewaydienst auf Anwendungsebene" gefunden und deaktiviert. Ist tatsächlich für ICS zuständig. Ist der Rechner über einen Router angeschlossen, funktioniert er dennoch einwandfrei. Wen es nervt: einfach den Dienst deaktivieren. Sascha
RatingICS File, alles im grünen Bereich ;-) greedy
RatingUsing NS Auditor, its in the system32 folder on XP and listens on 1035 Its flagged as; " Multidropper" Must be an exploitable MS service associated with MS firewall. Administrative Tools, and ZA blocking should help. There appears to be a lot of processes that attempt to , bypass and disable firewalls, and antispyware. Deserves a closer look! Geebee
Ratingsi apagas el firewall de windows sigue ahí; esta en WXp, sea SP1 o SP2; hace años que lo veo y no he tenido problemas nunca con el, excepto no saber que diables es. creo no es peligroso Conan
RatingIts a windows file, that can easily be comprimised by a virus or other malicious program God
RatingEs kann auch gut sein, dass diese exe. für die Firewall von Windows ist ; seit SP 2 auch wenn sie deaktiviert ist : (
RatingUsing NS Auditor, its in the system32 folder on XP and is listens on
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